UsableStats: View Answered Stats Questions

View Answered Questions

Search Questions :

Filter Questions :

Showing of 872 Questions

No. & Date Asked	Question
# 1050 :: 12/24/13	Suppose a sample of farmers is to be selected for estimating the cost of cultivation of maize per hectare. The precision is to be within 20 bi. . .
# 1049 :: 12/24/13	The same researcher wishes to estimate the proportion of executives who own a car phone. She wants to be 90% confident and be accurate within 5% of th. . .
# 1048 :: 12/24/13	A researchers wish to estimate, with 95% confidence, the proportion of people who own a home computer. A previous study shows the 40% of those intervi. . .
# 1047 :: 12/17/13	Which is the best approximation of the value of 730 − − − √ 3 ?. . .
# 1046 :: 12/16/13	You are conducting a study on what socio-demographic factors could be behind the behavioral problems of students. You are looking at how many times a. . .
# 1045 :: 12/15/13	how can i find the mean of the remaining observation if the mean of 30 observation is 5 and one of the value is 34?. . .
# 1044 :: 12/13/13	The Boss is a small Italian restaurant with 6 waiters and waitresses. The average service time at the restaurant for a table (of any size) in 80 minut. . .
# 1043 :: 12/4/13	A college is considering making the purchase of a laptop computer a requirement for some of its programs. In the past, only 20% of students. . .
# 1042 :: 12/4/13	If a random sample is to be drawn from a population consisting of 5000 sampling units with a variance of 20% and a desired standard error of 1.6%. Wha. . .
# 1041 :: 12/4/13	Let x̄1 represent the mean of a random sample of size n1, selected from the population x 2 3 7 F(x) 1/3 1/3 1/3 and x̄2 represent the m. . .
# 1040 :: 12/3/13	50 machine 5000kg cotton 8 hours 25 machine x cotton 12 hours. . .
# 1039 :: 11/30/13	"Holding all other elements equal, an increase in sample size will result in a wider confidence interval." I want to understand why this is true, I th. . .
# 1038 :: 11/28/13	A manufacturer of small appliances purchases coffeepot handles from an outside vendor. If a handle is cracked, it is considered defective and can't be. . .
# 1037 :: 11/28/13	A random sample will be selected from the adult residents of a particular city, the sample proportion will be used to estimate p, the proportion of al. . .
# 1036 :: 11/23/13	IQ test was administered to 5 person before and after they are trained. The result are given below: 10 Candidates: I II III IV V IQ before training. . .
# 1035 :: 11/23/13	IQ test was administered to 5 person before and after they are trained. The result are given below: 10 Candidates: I II III IV V IQ before training. . .
# 1034 :: 11/22/13	The heights of 20- to 29-year-old females are known to have a population standard deviation 1) �� = 2.7 inches. A simple random sample . . .
# 1033 :: 11/20/13	IQ test was administered to 5 person before and after they are trained. The result are given below: Candidates: I II III IV V IQ before train. . .
# 1032 :: 11/18/13	Assume that a random sample is used to est. a population proportion p. find margin of error E that corresponds to the given statistics and confidence . . .
# 1031 :: 11/5/13	the length of country and western songs is normally distributed and has a mean of of 170 seconds with a standard deviation of 49 seconds. find the pro. . .
# 1030 :: 11/5/13	the length of country and western songs is normally distributed and has a mean of of 170 seconds with a standard deviation of 49 seconds. find the pro. . .
# 1029 :: 10/30/13	Find the z-scores that bound the middle 15% of the standard normal distribution. (Give your answers correct to two decimal places.). . .
# 1028 :: 10/26/13	Some national statistics indicate the self-reported number of minutes per week of exercise is μ = 96.8 among college students. At the University . . .
# 1027 :: 10/24/13	if you have more than one situation(variance) occurring in the same case do you multiply the success rates for each or average them to get the final . . .
# 1026 :: 10/23/13	the standard deviation of the average scores on the SAT with mean 501 and standard deviation 112 and SRS of 100 students. . .
# 1025 :: 10/22/13	Although cities encourage carpooling to reduce traffic congestion, most vehicles carry only one person. For example, nationally 75.5% of the people dr. . .
# 1024 :: 10/22/13	Although cities encourage carpooling to reduce traffic congestion, most vehicles carry only one person. For example, nationally 75.5% of the people dr. . .
# 1023 :: 10/18/13	The mean and standard deviation for the quality point averages of a random sample of 36 college seniors are calculated to be 2.6 and 0.3, respectively. . .
# 1022 :: 10/13/13	State the different type of probability distribution of the continuous random variable. . .
# 1021 :: 10/13/13	In studying the behavior of air support roofs, the random variables X, the inside barometric pressure (in inches of mercury) and Y, the outside barome. . .
# 1020 :: 10/13/13	The applicants require to take the university examination for admission in engineering collage. Scores on the university are roughly normally distrib. . .
# 1019 :: 10/3/13	Professor gill selects 20 digits from the table and even digit tells her to use a true statement and odd tells her to use a false statement.. Using a . . .
# 1018 :: 9/29/13	detailed description of -the mean deviation about for the numbers 4/11, 6/11, 8/11, 9/11, 12/11. 8/11 is and 2nd question is the mean and SD for a,b . . .
# 1017 :: 9/27/13	To examine the effectiveness of its four annual advertising promotions, a mail order company has sent a questionnaire to each of its customers, asking. . .
# 1016 :: 9/27/13	The advertising firm of McMann and Tate has put out bids for two separate contracts. Based on past experience, they believe that they have a 0.7 proba. . .
# 1015 :: 9/27/13	Suppose that the number of customers who enter a supermarket each hour is normally distributed with a mean of 570 and a standard deviation of 170. The. . .
# 1014 :: 9/27/13	Suppose that the number of customers who enter a supermarket each hour is normally distributed with a mean of 570 and a standard deviation of 170. The. . .
# 1013 :: 9/27/13	A 12 ounce bottle of beer has 355 ml. The Random Brewing Company sets its machinery so that the contents of a bottle is normally distributed with a me. . .
# 1012 :: 9/26/13	median of (4,7,9,3,2)power1/4. . .
# 1011 :: 9/26/13	median of (4,7,9,3,2)power1/4. . .
# 1010 :: 9/24/13	If the mean is 24 inches and the SD is 4.5 inches, What is the height of a plant with a z score of 0? My question is what is the formula used to sol. . .
# 1009 :: 9/19/13	the probability that husband and wife will b alive after 20 years from now is 0.8 and 0.9 respectively.find the probability that in 20 years time 1. b. . .
# 1008 :: 9/16/13	Do creative people make better salespeople? Ten sales staff in a large company were given a creativity test (scores range from 0 to 20, with higher s. . .
# 1007 :: 9/16/13	Do creative people make better salespeople? Ten sales staff in a large company were given a creativity test (scores range from 0 to 20, with higher s. . .
# 1006 :: 9/16/13	Do creative people make better salespeople? Ten sales staff in a large company were given a creativity test (scores range from 0 to 20, with higher s. . .
# 1005 :: 9/16/13	Do creative people make better salespeople? Ten sales staff in a large company were given a creativity test (scores range from 0 to 20, with higher s. . .
# 1004 :: 8/29/13	three vehicles with a carrying capacity of 12 passengers each are used to ferry 30 international tourists and 5 local tourists from or tambo airport t. . .
# 1003 :: 8/28/13	In a BMT class test the scores of 8 students are: 11; 10; 6; 3; 11; 10; 9; 11. Assume the sores are a simple random sample from a normally distributed. . .
# 1002 :: 8/25/13	this is a test. . .
# 1001 :: 8/24/13	The following data gives gender and employment status of civilian labour force age 16 to 24 years as of March, 2006. Employed . . .
# 1000 :: 8/21/13	Fire Insurance is a business based on risk. If the mean cost of a fire is µ = £300 per person and the standard deviation is σ = 400. . .
# 999 :: 8/4/13	The mean serum cholesterol level of 25 men ages 65-74 is 231, with a sample standard deviation of 50. For 25 women of the same age, the mean serum ch. . .
# 998 :: 8/1/13	The mean of a normally distributed group of weekly incomes of a large group of executives is $910 and the standard deviation is $100. What is the z-sc. . .
# 997 :: 7/19/13	I am analyzing survey data from one university. Data set #1includes prenursing experience without a clinical experience in older adults. Data set #2. . .
# 996 :: 7/12/13	how do we calculate the confidence interval based on the population standard deviation. . .
# 995 :: 7/3/13	I amusing 20 participants to study whether a new drug is more effective than the current drug in the treatment of schizophrenia before they mass produ. . .
# 994 :: 7/2/13	4. Suppose that 100 people are given lipid lowering drugs and that the drug appears to be effective in about 20 of them. Effective is defined as lowe. . .
# 993 :: 6/29/13	a bank manager recorded the number of hours taken to accomplish a particular task. He got the data below. Hours:10, 11, 12, 13, 14, 15, 16, 17, 18. Nu. . .
# 992 :: 6/24/13	A test is given to graduates of tw buisness schools A and B. The scores are given out of 100. Test whether the school differ in quality by using Mann-. . .
# 991 :: 6/22/13	In an industry,200 workers,employed for a specific job,were classified according thier performance and training received/not received to test indepen. . .
# 990 :: 6/22/13	Two impendent samples of signs 9 and 8 gave the sum of squares of deviation from their respective means as 160 and 91 can the samples be regarded as d. . .
# 989 :: 6/16/13	The Ministry of Environment, Science and Technology has one of its administrative centers located out of town and the majority of employees drive to w. . .
# 988 :: 6/8/13	A drug company want to know if new drug lowest the cholesterol below the target level of 120.A random sample of 25 questions has a mean of 115 and a s. . .
# 987 :: 5/14/13	1000 students had written an examination the mean of test is 35and standed deviation is 5. Assuming the distribution to be normal find 1. how many. . .
# 986 :: 5/6/13	general scores on academic performance in english language using 60 participant. let the highest score be 90 and 10. use a class inertval of 10 create. . .
# 985 :: 4/16/13	Usablestats.com Team, I thought you might like to know some reasons why you are not getting enough Social Media and Organic search engine traffic f. . .
# 984 :: 4/16/13	a sample of 35 workers was randomly selected from a workforce of 110 to estimate the average amount spent weekly at a canteen by each worker.the sampl. . .
# 983 :: 4/11/13	find the standard deviation from the fallowing data. Wages-0-5, 5-10, 10-15, 15-20, 20-25, 25-30, 30-35, 35-40. No. Of workers-2, 5, 7, 13, 21, 16, . . .
# 982 :: 3/27/13	My question has to do with power. Suppose in a clinical study you have two groups with 10 subjcects in each group. No significance at the .05 level is. . .
# 981 :: 3/27/13	For Question 980 you Submitted Question : 1. Does dichotomizing the dependent variable (i.e. logistic regression) decrease power in relation . . .
# 980 :: 3/27/13	1. Does dichotomizing the dependent variable (i.e. logistic regression) decrease power in relation to a continuous dependent variable? I noticed the l. . .
# 979 :: 3/26/13	the average cost for service provided per person per day is random variable with normal distribution of N$ 100 and a standard deviation of N$ 22. Wha. . .
# 978 :: 3/25/13	why we need to measure variability?. . .
# 977 :: 3/3/13	British airways employs you as cunsultant to analyse the departure time of flight leaving Cape Town International Airport. The acceptance time frame f. . .
# 976 :: 2/20/13	Can you give examples of Ratio,Nominal,Ordinal and Interval and how these terms relate to business. . .
# 975 :: 2/13/13	is farm size a discrete or continuous data?. . .
# 974 :: 1/19/13	1. A population of size 1,000,000 claims has mean cycle time of 15 days, and a standard deviation of 4. 100 random samples of each size 64 are selecte. . .
# 973 :: 1/12/13	write a short note on lorenz curve. . .
# 972 :: 12/15/12	In Eurelia there are three categories of bicycle license, with different fees for each. The table below is based on a random sample of 122 Eurelian b. . .
# 971 :: 12/7/12	1. A few years ago, the Food and Drug Administration issued a strong warning against Procter & Gamble’s Rely tampon. The study of toxic shock syndrome. . .
# 970 :: 12/6/12	Suppose you wish to test the effect of a new medication (X) compared to Prozac on the well-being of depressed individuals, using a standardized "well-. . .
# 969 :: 11/22/12	In May 1998, the New York Times carried an article by Adam Bryant describing a research project to relate two rather diverse phenomena: the performanc. . .
# 968 :: 11/18/12	a self proclaimed psychic was tested with 100 cards face downand asked to determine what symbol, out of 5 possible symbols the card hado n it. How man. . .
# 967 :: 11/17/12	The table below shows the weights (in pounds) of 6 randomly selected women in each of three different age groups. Use a 0.01 significance level to tes. . .
# 966 :: 11/9/12	During the 2000 season, the home team won 138 of the 240 regular season National Football League games. Is this strong evidence of a home field advant. . .
# 965 :: 10/31/12	Go to the online library and find a recent (no older than 3 years) article reporting the results of a nursing or health research study in which a stat. . .
# 964 :: 10/31/12	Designing a study Create an example of a research question in an imaginary quantitative NURSING study you might design. Identify the independent and. . .
# 963 :: 10/31/12	In traditional marketing research surveys, are purchase intent questions measured on a 5 point scale (e.g. definitely would buy, probably would be, et. . .
# 962 :: 8/28/12	1. was the target goal reached for reameasurement period 1 or 2? 2. provide a quantitative analysis that compares remeasurement 1 and 2 data to the b. . .
# 961 :: 6/25/12	assume that an apptitude test are normally distributed. if the mean score in on 140 points and standard deviation is 25 points. find the cut off passi. . .
# 960 :: 6/21/12	a random sample of 50 men, 40% said they preferred walking up stairs than taking the elevator. In a random sample of 40 women, 50% said they preferred. . .
# 959 :: 6/9/12	I need to determine whether a marketing campaign to increase spending at a direct marketing retailer has resulted in incremental spend. For this campa. . .
# 958 :: 6/9/12	dsfdsf. . .
# 957 :: 5/23/12	a researcher reports a mean pulse rate of 80 for the ampled patients. the data also revealed a standard deviation of 10.5. what percent of patients pu. . .
# 956 :: 5/15/12	In a population of 5000 students, a simple random sample of 50 students is selected in order to estimate the weighted average mark for the population.. . .
# 955 :: 5/9/12	During nine days in a festival, the highest sale of a shop was on sunday and was 900„5 more than the average sale for other days. If the standard dev. . .
# 953 :: 5/4/12	23 parents asked It is fun to read with my child....stats = mean 4.61 median 5.00 standard deviation .499. . .
# 952 :: 5/4/12	23 parents were given a family reading survey....They were asked if they liked to read? The mean stats came back 4.00 The median stats 5.00 The stan. . .
# 951 :: 4/30/12	1. A research team conducted a study of soft- drink preferences among residents in a test market prior to an advertising campaign for a new cola produ. . .
# 950 :: 4/30/12	A sample of 10 electronic tubes produced by a company showed a mean lifetime of 1200 hours and a standard deviation of 100 hours. estimate the mean an. . .
# 949 :: 4/29/12	The desired percentage of silicon dioxide in a certain type of cement is 5. A random sample of 36 specimens gave a sample average percentage of 5.21 a. . . 1-sample t-test
# 948 :: 4/29/12	It is important for airlines to know the approximate total weight of the baggage carried on each airplane. An airline researcher believes that the mea. . . 1-sample Z-test
# 947 :: 4/29/12	Workers in 2 different mine groups were asked what they considered to be the most important labour-management problem. In Group A, 200 out of a random. . . 2-proportion test
# 946 :: 4/29/12	The management of a mine wishes to investigate the effect of a 4-day workweek on absenteeism. 2 random sample of size 40 were selected. Employees of G. . . 2-sample t-test
# 945 :: 4/29/12	In a survey of 1000 electors, 20% were found to favour party "stats". 1. Construct a 95% C.I for the percentagew in favour of party "stats". 2. What. . . Confidence Intervals, Sample Size
# 944 :: 4/29/12	Mr. price Home analyzed the value of purchase made on credit by a sample of 25 credit card customers. The simple mean was found to be R170.08 with a s. . . Confidence Intervals
# 943 :: 4/27/12	Suppose the Total Sum of Squares for a design with k=6 treatments and n=36 total measurements (six per treatment) is equal to 500. In each of the foll. . .
# 942 :: 4/19/12	Please kindly help me with this Cost Benefit Analysis Proposal for New Employee. Please provide work in detailed step by step instructions thank you v. . .
# 941 :: 4/15/12	Problem 3: A group of college students were surveyed to learn how many times they had visited a dentist in the previous year. The probability distribu. . .
# 940 :: 4/13/12	solution to managerian stastics question. suppose that a consultant for the supermarket counts the number of arrival per hour during a sample of 150 h. . .
# 939 :: 4/5/12	When using a t test for dependent means, show the steps involved in calculating the estimated population variance based on scores in this sample: Par. . .
# 938 :: 4/4/12	random sample of 100 pieces of wire and wants to see if the thickness of a batch of wire meets minimum specifications. Assume that the population mea. . .
# 937 :: 3/30/12	frequency and relative frequency distribution. use 7 classes of width 1.30 starting point 1.15 sample 26.... How will u do this im so lost.... The dec. . .
# 936 :: 3/26/12	You are interested in evaluating a new treatment for heart disease. (a) Discribe the population of interest. (b) Describe how you might obtain a rando. . .
# 935 :: 3/25/12	I have two samples populations and want answer the question as to whether the difference in the means of the two samples are statisticall significant. . .
# 934 :: 3/17/12	The data shown represent the scores on a national achievement test for a group of 10th grade students. Find the approximate percentile ranks of these. . .
# 933 :: 3/17/12	Determine whether the New York Yankees or the Philadelphia Phillies had a relatively better runs producing season. The Yankees scored 960 runs and pl. . .
# 932 :: 3/13/12	ou measure the weights of a random sample of twenty-five male runners. The sample mean is 60 kilograms (kg). Suppose that the mean weights of male r. . .
# 931 :: 3/13/12	to find total and average of 3 subjects. . .
# 930 :: 2/21/12	Consider the ibuprofen function I(t) = 210110tt. I is in mg of ibuprofen and t is in hours. 1. Use the FACTORING method to find the t. . .
# 929 :: 2/18/12	The following observations are weights of 10 potatoes in grams. Calculate the percentage of potatoes with weights greater than 25 grams and the range . . .
# 928 :: 2/17/12	what will be the standard deviation and the varience in each of the following casses (i) 2x (ii)2+x (iii) 2x+4 if var(x)=25. . .
# 927 :: 2/2/12	A company that manufactures computer chips wants to use a multiple regression model to study the effect that different variables have on y, the total . . .
# 926 :: 1/30/12	A survey of random sample of people leaving an amusement park showed an average expenditure number 10.30k for the evening, the average of expenditure . . . weighted mean
# 925 :: 1/30/12	3 section of a statistics class containing 28,32 and 35 students averaged 83,80 and 76 respectively on same final exam. what 's the combined populatio. . . weighted mean
# 924 :: 1/23/12	Given the sample dataset of size n = 5: {2, -4, 1, 1, 5x}. Note that x is a real number. Obtain the empirical influence function for the mean an. . .
# 923 :: 1/23/12	The average life span of American male professors is 75.6 years, but standard deviation is unknown. A random sample of n = 5 recently (last 10 ye. . .
# 922 :: 1/23/12	A random sample of measurements on two quantitative variables x and y is taken from a population. The data for the variables x and y are: {(x,. . .
# 921 :: 1/23/12	Consider the finite population of size N = 3, measurements on the variable x: {2, 3, 4}: a. derive the population probability distribution for the . . .
# 920 :: 1/13/12	The average service time at CheesePlate Restaurant is 3.5 minutes with a standard deviation of .04 minutes. A new order system claims it can improve . . . 1-sample t-test
# 919 :: 1/12/12	income and daily expense.the two variable will consider as discrete or continuous?. . .
# 918 :: 1/12/12	what is mode?. . .
# 916 :: 1/9/12	what is the diffrence betweenqualitative data and nominnnal data?. . .
# 915 :: 12/6/11	create a 95%confidence interval for the value of the population mean, given that their is a sample mean of 49 and a standard deviation of 3 but now fo. . . 1-sample t-test, Confidence Intervals
# 914 :: 12/6/11	create a 95% confidence interval for the value of the population mean, given that their are 64 observations and a sample mean of 49, with a sample sta. . . 1-sample t-test, Confidence Intervals
# 913 :: 12/5/11	The mean is 112 oz, and the standard deviation is 40 oz. Compute the probability that the mean from a sample of 49 will fall between 103 and 121 oz. . . Z-Score, Area between, Standard Error of the Mean
# 912 :: 12/3/11	Find the appropriate critical statistic for a two tailed test with 20 observations and alpha equal to 0.05.. . . Critical Value, t-statistic
# 911 :: 12/3/11	Find the critical statistic for a one tailed test in the negative direction with 25 observations and alpha equal 0.01.. . . Critical Value, t-statistic
# 910 :: 12/3/11	Find the appropriate critical statistic for : A one tailed test in the positive direction with 15 observations with alpha equal to 0.001.. . . Critical Value, test statistic
# 909 :: 12/3/11	Find the critical statistic for: A two tailed test with 50 observations with alpha equal to .001.. . . Critical Value, t statistic
# 908 :: 12/3/11	Create a 90% confidence interval for the value of the population mean using the following information: A sample mean of 65, a sample standard deviatio. . . 1-sample t-test
# 907 :: 12/3/11	Suppose that you have a sample mean of 49 and a standard deviation of 3, but now found those values from a sample of 20 observations. test the hypothe. . . 1-sample t-test
# 906 :: 12/3/11	You want to test the hypothesis that the mean age for teachers is equal to 50. If you take a sample of 64 observations and find a sample mean of 49, w. . . 1-sample t-test
# 905 :: 12/3/11	create a 95% confidence interval for the value of the population mean using the following information: a sample mean of 55, a sample standard deviatio. . . Confidence Intervals
# 904 :: 10/24/11	Use MINITAB to generate 1200 individual values from a Standard Normal distribution (mean = 0, std. dev = 1).. . .
# 903 :: 10/16/11	Consider a random sample of 9 observations, from a Normal distribution, with sample average 25.0. a) Calculate a 95% confidence interval for the p. . .
# 900 :: 9/28/11	Suppose we want to design a new placebo-controlled trial to evaluate an experimental medication to increase lung capacity. The primary outcome is pea. . .
# 899 :: 9/5/11	In a study , the average age of the male candidates who were affected , was 38.20 whereas the average age of the female subjects was calculated to 34. . . Variance, Standard Deviation
# 898 :: 8/1/11	Hi, I believe this question may require a few back n forth emails from us as I'm not sure if I will cover everything that is required for you to an. . .
# 897 :: 7/27/11	What is the probability for the following values of Z? a. Z < 1.35 b. Z > -1.84 and Z < 2.52 c. Z < 1.02 and Z > 2.77. . . Area between, Z-Score
# 896 :: 7/26/11	1. Given the following probability distributions: Group A X P(X) 2 0.15 4 0.20 6 0.25 8 0.15 10 0.25 a. Compute the expected v. . . Expected Value
# 895 :: 7/19/11	In a sample of n = 36 selected from a population, where X = 96 and S = 12, what is the value of tSTAT if you are testing the null hypothesis H0: µ = 1. . . 1-sample t-test, test statistic
# 894 :: 7/17/11	Can percentages be converted to z score?. . . Z-Score
# 893 :: 7/12/11	Elbow to fingertip length of men 99% confidence n=32, x- 14.50,s= 0.70 what is the margin of error. . . Margin of Error, Confidence Intervals
# 892 :: 7/11/11	42 people judged their emotional response to six typeface designs. There were 12 buttons to present the emotions visually (via animated characters). P. . .
# 891 :: 6/25/11	X, Y, and Z are independent normally distributed random variables. The following information is known about these three variables: E (X) =4, . . .
# 890 :: 6/14/11	I've a set of related questions on power analysis. Suppose I have an experiment with 5 groups and 5 DVs and intend to conduct MANOVA to determine . . . MANOVA, Power
# 889 :: 5/29/11	2. The figure below is a Normal quantile plot of the emissions of carbon dioxide (CO2) per person in 48 countries. The data set can be found under Ass. . .
# 888 :: 5/29/11	1. Too much cholesterol in the blood increases the risk of heart disease. Young women are generally less afflicted by high cholesterol than other grou. . .
# 887 :: 5/29/11	1. Too much cholesterol in the blood increases the risk of heart disease. Young women are generally less afflicted by high cholesterol than other grou. . .
# 886 :: 5/2/11	ok i will wait for my answer.. . .
# 885 :: 5/2/11	as i study on childhood disease then my collected sample is 269 and variable include age of child ,vaccination status , social condition include type . . .
# 884 :: 5/1/11	1The following data represent the results from an independent-measures study comparing three treatments. Treatment I II III n = 10 n = 10 n = 10 . . .
# 883 :: 4/1/11	In studying satisfaction patients have with an operation I have 2 random groups each given a different questionaire. I want to compare the responses o. . .
# 882 :: 3/24/11	8. For the preceding problem you should find that there are significant differences among the three treatments. The primary reason for the significa. . .
# 881 :: 3/24/11	6. The following data represent the results from an independent-measures study comparing three treatments. a. Compute SS for the set of 3 treatment. . .
# 880 :: 3/24/11	Describe the similarities between an F-ratio and a t statistic.. . . t-statistic, F-statistic
# 879 :: 3/14/11	What is statistical significance of p-value. . .
# 878 :: 1/16/11	Banner Mattress and Furniture Company wishes to study the number of credit applications received per day for the last 300 days. To interpret, there. . . Chi-Square Goodnes of Fit Test, Poisson Distribution
# 877 :: 1/13/11	Suppose that the sales manager of a large automotive parts distributor wants to estimate as early as April the total annual sales of a region. On the. . . Regression Analysis
# 876 :: 1/8/11	A suburban hotel derives its gross income from its hotel and restaurant operations. The owners are interested in the relationship between the number o. . . Scatter Plot, correlation coefficient
# 875 :: 1/8/11	The amount of income spent on housing is an important component of the cost of living. The total costs of housing for homeowners might include mortgag. . . Paired t-test
# 874 :: 1/3/11	Martin Motors has in stock three cars of the same make and model. The president would like to compare the gas consumption of the three cars (labeled c. . . ANOVA
# 873 :: 1/3/11	During recent seasons, Major League Baseball has been criticized for the length of the games. A report indicated that the average game lasts 3 hours a. . . 1-sample t-test
# 872 :: 12/7/10	Discuss how a t Test for a dependent variable can be of great value in applying a new approach to the treatment of aggressive behavior to a small grou. . .
# 870 :: 11/6/10	A hospital in California uses 100.6 degrees Fahrenheit as the lowest temperature considered to indicate a fever. What percentage of normal and health. . . Z-Score
# 869 :: 10/14/10	You need to estimate the mean Christmas sales across a large chain of jewelry stores. You want to estimate this mean value to within $100 with 99% co. . . Sample Size
# 868 :: 10/14/10	Suppose that a 90% confidence interval for a population mean μ is constructed from a sample, resulting in the interval from 120 to 150. What was. . . Confidence Intervals, Margin of Error
# 867 :: 10/11/10	A manufacturer wants to increase the absorption capacity of a sponge. Based on past data, the average sponge could absorb 3.5 ounces. An organic candl. . .
# 866 :: 10/9/10	A study showed 118 instances of breast cancer among 3,303 mothers who used diethylstibestrol (DES), an estrogen-like substance formerly used to preven. . .
# 864 :: 4/15/10	1. Suppose a 95% confidence interval for the mean daily sales for a sample of 100 days from an internet site is:($236, $318). a. Will a 99% confidenc. . .
# 863 :: 4/12/10	Describe how measurements and regression analysis are interpretations of reality and not reality itself. (One page answer). . .
# 862 :: 4/12/10	A recent survey of community colleges found the average age of attending students to be 29. A class of 24 students has a mean age of 26 and a standard. . .
# 861 :: 4/8/10	Lab 6, confidence intervals, two sample and paired In class we discussed GM testing a brake light. Suppose that this is very expensive, time-consum. . .
# 860 :: 3/30/10	Problem # 1: Clothing for Runners: Your company sells exercise clothing and equipment on the internet. To design the clothing, you collect a data on. . . Confidence Intervals, Margin of Error
# 859 :: 3/18/10	1) Spinifex pigeons are one of the few bird species that inhabit the desert of Western Australia. The pigeons rely almost entirely on seeds for food. . . . Confidence Intervals
# 858 :: 3/18/10	A questionnaire about study habits was given to a random sample of students taking a large introductory statistics class. The sample of 25 students re. . . Margin of Error
# 857 :: 3/17/10	A drug manufacturing company conducted a survey of customers. The research question is: Is there a significant relationship between packaging preferen. . . Chi-Square Test of Independence
# 856 :: 3/14/10	In this case, we are going to study some data collected from Kelly Blue Book for several hundred 2005 used General Motors (GM) cars. This data allows . . . Regression Analysis
# 855 :: 3/6/10	Random samples of five were selected from each of three populations. The sum of squares total was 100. The sum of squares due to the treatments was 4. . . ANOVA Summary Data
# 853 :: 3/6/10	A recent study focused on the number of times men and women who live alone buy take-out dinner in a month. The information is summarized below. Stat. . . 2-sample z-test
# 852 :: 3/5/10	There are four entrances to the Government Center Building in downtown Philadelphia. The building maintenance supervisor would like to know if the en. . . Chi-Square Goodnes of Fit Test
# 851 :: 3/5/10	In a particular market there are three commercial television stations, each with its own evening news program from 6:00 to 6:30 P.M. According to a r. . . Chi-Square Test of Independence, Chi-Square Goodnes of Fit Test
# 850 :: 3/5/10	The following is a partial ANOVA table. Source sum of Squares df . . . ANOVA Table, ANOVA
# 849 :: 3/5/10	A real estate agent in the coastal area of Georgia wants to compare the variation in the selling price of homes on the oceanfront with those one to t. . . F-test
# 848 :: 3/5/10	The president of the American Insurance Institute wants to compare the yearly costs of auto insurance offered by two leading companies. He selects a . . . Paired t-test
# 847 :: 3/5/10	Grand Strand Family Medical Center is specifically set up to treat minor medical emergencies for visitors to the Myrtle Beach area. There are two fac. . . 2-sample t-test
# 846 :: 3/2/10	A recent article in The Wall Street Journal reported that the 30-year mortgage rate is now less than 6 percent. A sample of eight small banks in the . . . 1-sample t-test
# 845 :: 3/2/10	Dole Pineapple, Inc., is concerned that the 16-ounce can of sliced pineapple is being overfilled. Assume the standard deviation of the process is .03. . . 1-sample t-test, 1-sample Z-test
# 844 :: 3/2/10	A new weight-watching company, Weight Reducers International, advertises that those who join will lose, on the average, 10 pounds the first two weeks. . . 1-sample t-test, 1-sample Z-test
# 843 :: 2/27/10	Braking distances of cars. A random sample of 13 four-cylinder cars is obtained and braking distances are measured and found to have a mean of 137.5 . . . Standard Deviation, Two Variances, F-statistic
# 842 :: 2/18/10	what statistic method is best used to test 'the influence of persons on behaviour of other persons? thank you.. . .
# 840 :: 2/11/10	Sat verbal scores are normally distributed with a mean of 426 and a standard deviation of 94. Use the Empirical Rule to determine what percent of the. . . Empirical Rule
# 838 :: 2/9/10	using the full 5-step process test to see if a population mean is not 25. Sample data is: Mean 24, standard deviation 10 and a sample of 400 was taken. . . 1-sample t-test
# 836 :: 1/13/10	a statistician was setting up a hypothesis test with a level of significance dictated by upper management. However, she was concerned that the test wo. . . Type II Error, Sample Size
# 835 :: 12/12/09	• Analyze the following two data sets: o In Statistics Alive, Module 35, p. 410–411, data are presented for 15 persons regarding high. . .
# 834 :: 12/9/09	You are interested in testing the hypothesis that men have greater levels of political participation than women, so you survey 332 men and 375 women . . . 2-sample t-test, Hypothesis Test
# 833 :: 12/9/09	suppose that the census indicates the average American earns $36,345.45 per year. You are interested in the whether people who majored in political s. . . Hypothesis Test, 1-sample t-test
# 832 :: 12/8/09	1.What are the underlying assumptions of Spearman rank-order scale? 2.What happens when a stanine is more than 9?Explain.. . .
# 831 :: 12/3/09	I have a humor appreciation survey with 40 items and 500 participants. The items were interpreted and classified by a theory into four classes of 10 i. . .
# 830 :: 11/24/09	A psychologist is studying the distribution of IQ scores of girls at an alternative high school. In wishing to estimate the average IQ scores in this . . .
# 824 :: 11/8/09	The grades on a statistics midterm test are normally distributed with a mean of 78 and a standard deviation of 6 a. What proportion of the class has . . . Z-Score, Standard Error of the Mean
# 823 :: 10/22/09	What is an 'effect size' ? When is it used ? Why is it used in educational research?. . . Effect Size, Cohen d
# 822 :: 10/19/09	Jeff... the previous answer was not quite the answer I was anticipating- let me restate the problem more clearly. 1. A manufacturer has a process whi. . .
# 821 :: 10/18/09	A manufacturer can typically process 176-264 devices a given period of concern. In this situation the processing event is either pass or fail. There i. . . Power, Sample Size, Effect Size, 1-Proportion Test
# 820 :: 10/17/09	An animal trainer obtained the following sample data (Table A) in a study of reaction times of dogs (in seconds) to a specific stimulus. He then selec. . . Standard Deviation, Standard Deviation on Frequency Data, Standard Deviation of Grouped Data, F-test
# 819 :: 10/15/09	For a particular sample of 50 scores on a psychology exam, the following results were obtained. First quartile = 52 Third quartile = 84 Standard dev. . . Chebyshev's Theorem, Midrange, Empirical Rule
# 817 :: 10/8/09	1) Assuming in New York 80% of women and 50% of men know where Tiffany is. At a crossing I ask pedestrians for directions to Tiffany and get these ans. . . Binomial Probability
# 815 :: 10/5/09	Shaver Manufacturing, Inc., offers dental insurance to its employees. A recent study by the human resource director shows the annual cost per employee. . . Z-Score, Area between
# 814 :: 10/4/09	in a school how is ztest used in time table ... one group that studies 7 periods a day of 45 mins each class and the other group can choose semester w. . . 2-sample z-test, 2-sample t-test
# 813 :: 10/2/09	Serum cholesterol levels were taken from a population of 10,000 college students. The results were normally distributed. Males had a mean of 195 and a. . . Z-Score, NORMSDIST
# 812 :: 10/2/09	A Tamiami shearing machine is producing 10 percent defective pieces, which is abnormally high. The quality control engineer has been checking the outp. . . BINOMDIST, Binomial Probability
# 811 :: 10/1/09	Discuss the assumptions for using a chi-square test. Research articles using and provide practical examples from the reseach to support your assumptio. . .
# 806 :: 9/7/09	Discuss how the statistical application of Pearson r is used for hypothesis testing.l Through application of the Spearman Correlation discuss what ty. . . Pearson r, Spearman Correlation
# 804 :: 8/29/09	The mean on this test is 3.5 with a standard deviation of .5. Sally scores 1.5 on this test. How many standard deviations is Sally from the mean?. . . Z-Score
# 803 :: 8/28/09	In a study, the sum of squared deviations from the mean for the sample is 12 and there are 4 participants. What is the estimated population variance?. . . Variance
# 802 :: 8/27/09	type of research where using the t statistic may be an appropriate alternative to using a z-score. . . t statistic
# 798 :: 8/19/09	Teens were asked in the MTF 2006 survey how often they think about social issues (specific issues were not identified). The bivariate table includes r. . . Chi-Square, Chi-Square Test of Independence
# 797 :: 8/15/09	The issue of how much should be spent to solve particular U.S. social problems is a complex matter, and people have diverse and conflicting ideas on t. . . Chi-Square
# 796 :: 8/13/09	Very happy Not happy at all Mean ideal number of children 3.32 2.07 Standard deviation . . . 2-sample t-test
# 795 :: 8/13/09	Data from the MTF 2006 survey reveal that 71.5% (432 out of 604) of males and 74% (562 out of 756) of females reported trying alcohol. You wonder whe. . . 2-proportion test
# 794 :: 8/10/09	A psychologist has developed a test to measure self-control. The test is normed so that it has a mean of 100 and a standard deviation of 15... The s. . . Z-Score, Percent Score, Percentile Rank, Area between
# 793 :: 8/8/09	For the total population of a large southern city, mean family income is $34000, with a standard deviation (for the population) of $5000. a. imagi. . . Z-Score
# 792 :: 8/7/09	send the standard normal table. . .
# 791 :: 8/4/09	Serum cholesterol levels were taken from a population of 10,000 college students. The results were normally distributed. Males had a mean of 195 and a. . . Z-Score
# 790 :: 7/31/09	As a condition of employment, Fashion Industries applicants must pass a drug test. Of the last 220 applicants 14 failed the test. Develop a 99 percent. . .
# 789 :: 7/31/09	A state meat inspector in Iowa has been given the assignment of estimating the mean net weight of packages of ground chuck labeled “3 pounds.” Of cour. . .
# 788 :: 7/31/09	A recent survey of 50 executives who were laid off from their previous position revealed it took a mean of 26 weeks for them to find another position.. . .
# 787 :: 7/30/09	Below are fertility rates (average children born per woman) in 15 EU nations for 2 years. (a) Make a scatter plot. (b) Find the correlation coefficie. . . correlation coefficient , significant correlation, Pearson r
# 786 :: 7/27/09	From her firm’s computer telephone log, an executive found that the mean length of 64 telephone calls during July was 4.48 minutes with a standard de. . . 2-sample t-test
# 784 :: 7/21/09	Two manufacturing facilities produce 1280 × 1024 LED (light-emitting diode) displays. Twelve displays are chosen at random from each lab, and the num. . . Mann Whitney
# 782 :: 7/14/09	A 20-minute consumer survey mailed to 500 adults aged 25–34 included a $5 Starbucks gift certificate. The same survey was mailed to 500 adults aged 2. . . 2-proportion test
# 781 :: 7/14/09	I am to do a study that involves people whose IQ are in the normal range 70 to 130. How many people must I screen with IQ test in order to find a samp. . . Sample Size
# 780 :: 7/14/09	Dear Mr. Sauro: In reference to you article, "Calculating a Sigma Level from Task Success," I found no references to “usability” nor “task completio. . . Usability, Six Sigma
# 779 :: 7/13/09	If all the values in a set are converted to z-scores, is the shape of the distribution of the z scores will be bell shape regardless of the distributi. . . Central Limit Theorem
# 778 :: 7/12/09	200 students took a test. The scores were normally distributed. Your score was in the 60th percentile. How many people scored at or below your score?. . . Percentile
# 777 :: 7/11/09	Suppose that the quarterly sales levels among health care information systems companies are approximately normally distributed with a mean of million. . .
# 776 :: 7/8/09	Clients at a Diabetic Education Program were randomly assigned to one of two learning programs. Group A participants attended a three-day, in-class. . .
# 775 :: 7/6/09	1.-A state meat inspector in Iowa has been given the assignment of estimating the mean net weight of packages of ground chuck labeled “3 pounds.” Of c. . . Confidence Intervals
# 774 :: 7/5/09	If I'm doing a multivariate linear regression in Minitab (about 40 variables), how to restrict all coefficients positive?. . . Linear Regression
# 773 :: 7/1/09	i have problem in run multiple linear regression which faced me a problem of heteroscadecity and i want solve it using weight least squares (wls) but . . .
# 772 :: 6/29/09	A random sample of 16 pharmacy customers showed the waiting times below (in minutes). Find a 90 percent confidence interval for Î¼, assuming that the . . .
# 771 :: 6/29/09	One-fourth of the residents of the Burning Ridge Estates leave their garage doors open when they are away from home. The local chief of police estimat. . . Bayes Theorem , Conditional Probability, Tree Diagram
# 770 :: 6/29/09	Dr. Stallter has been teaching basic statistics for many years. She knows that 80 percent of the students will complete the assigned problems. She has. . . Bayes Theorem , Tree Diagram
# 768 :: 6/26/09	A multiple choice test consists of 25 questions with possible answers of a, b, c, d, and e. Estimate the probability that with random guessing, the nu. . . Binomial pmf
# 767 :: 6/24/09	IQ scores are normally distributed with a mean of 100 and a std dev of 15. If 25 people are randomly selected for an IQ test, find the probably that . . . Z-Score
# 766 :: 6/23/09	A researcher has a series of Likert-scaled items and a measure of frequency of absenteeism. He uses each of the Likert-scaled items in a separate biva. . . Correlation, Non-Linear Correlation
# 765 :: 6/23/09	A football team's season ticket sales, percentage of games won, and number of active alumni for the years 1992-2000 are given below: Year . . . Regression Analysis
# 764 :: 6/23/09	Suppose Abraham Lincoln had answered a survey questionnaire in which he indicated that he had not received a grade school diploma. The researcher foun. . . Correlation
# 763 :: 6/18/09	Finding appropriate z- and t-scores is important when constructing confidence intervals. Confidence intervals allow one to estimate important populat. . .
# 762 :: 6/18/09	Bob enjoys making candy and some friends have encouraged him to open a candy-making business. To see if the local citizens buy enough candy, Bob gath. . .
# 761 :: 6/18/09	I need to know which formulas would be used to answer these two probability questions. 1. A certain airplane has two independent alternators to prov. . .
# 760 :: 6/17/09	. You are a researcher who conducted a study of soft-drink preferences among residents in a test market prior to an advertising campaign for a new co. . .
# 759 :: 6/15/09	A sample of 25 concession stand purchases at the May 12 matinee of Spider-Man 3 showed a mean purchase of $ 7.29 with a standard deviation of $ 3.02. . . .
# 758 :: 6/15/09	To test the hypothesis that students who finish an exam first get better grades, Professor Hardtack kept track of the order in which papers were hande. . .
# 756 :: 6/15/09	In Dallas some fire trucks were painted yellow (instead of red) to heighten their visibility. During a test period, the fleet of red fire trucks made. . .
# 755 :: 6/14/09	Interpret the following SPSS computer output for the chi-square test. Variable COMMUTE is “How did you get to work last week?” Variable GENDER is “Are. . . Chi-Square Test of Independence, SPSS
# 754 :: 6/14/09	Collapse the response categories in the following table so that it meets the assumption of the chi-square test; then perform the test. . . . Chi-Square Test of Independence
# 753 :: 6/14/09	Perform a chi-square test on the following data: (a) Regulation is the best way to ensure a safe workplace. . . .
# 752 :: 6/14/09	An Excel Spreadsheet is reprinted below. Interpret the t-test results. Are they statistically significant? t-Test: Paired Two Sample for Means Be. . . Paired t-test
# 751 :: 6/14/09	The managers in a company’s East and West regions were rated on the basis of the company’s evaluation system. A researcher wishes to conduct a t-test . . . 2-sample t-test
# 750 :: 6/14/09	Test the hypothesis of no differences for average payback period (years) necessary to justify solar heating systems for residences. Savings and Loa. . .
# 749 :: 6/14/09	A personnel manager has a computer-generated list of all employees that indicates that 70 percent are full-time employees, 20 percent are part-time em. . . Chi-Square Goodnes of Fit Test
# 748 :: 6/14/09	What test of differences is appropriate in each of the following situations? Why? (a) Average campaign contributions of Democrats, Republicans, and. . .
# 747 :: 6/13/09	A random sample of 46 observations was selected from a normally distributed population. The sample mean was xbar=81, and the sample variance was s2=3. . .
# 746 :: 6/12/09	a. Select a variable. Compare the mean of the variable for a sample of 30 for one group with the mean of the variable for a sample of 30 for a second . . .
# 745 :: 6/8/09	Calculate the average student score necessary for the district to retain its federal funding. You may assume that the Standard Deviation will not chan. . .
# 744 :: 6/6/09	Quality Motors is an automobile dealership that regularly advertises in its local market area. It claims that a certain make and model of car averages. . . 1-sample t-test
# 743 :: 6/6/09	Assume you have the following data: Ho: u = 2,450, S = 400, n = 100, and X = 2,300. Conduct a hypothesis test at the .01 significance level. **If the. . . 1-sample Z-test
# 741 :: 6/6/09	Assume you have the following data: Ho: u = 200, S = 30, n = 64, and X = 218. Conduct a two-tailed hypothesis test at the .05 significance level.. . . 1-sample Z-test
# 740 :: 6/6/09	After a bumper crop, a mushroom grower hypothesizes that mushrooms will remain at the average wholesale price of $1 per pound. State the null hypothes. . .
# 739 :: 6/4/09	How many data do we need as a minimum in order to calculate the z-score meaningfully?. . . Z-Score
# 738 :: 6/4/09	What value would be needed to complete the following probability distribution? x p (x) 0 . . . Random Variable, Expected Value
# 737 :: 5/31/09	(a) Choose one beverage category and plot the data (MILK CATAGORY CHOSEN). (b) Describe the trend (if any) and discuss possible causes. (c) Would a f. . . Time-Series
# 736 :: 5/28/09	A student heard that the average household watches 26.4 hours of t.v. per week, with a stand.dev. of 2.3 hours. He decided to run his own experiment . . . 1-sample Z-test
# 735 :: 5/25/09	how does a confidence interval this relate to learning statistics How do you think confidence intervals are useful in the real-world?. . . Confidence Intervals
# 733 :: 5/24/09	The data in the following tables are some of the results of an Internal Revenue Service survey of taxpayers. Analyze and interpret the data. -The las. . .
# 732 :: 5/23/09	You have asked to research the high absenteeism rate in your company. One required analysis is to be by gender. Assume you have been asked to do the . . .
# 731 :: 5/23/09	Test to see if four population means are the same or different. Assume the populations are normally distributed and have equal variances. Use the fo. . . ANOVA Summary Data
# 730 :: 5/23/09	Describe the steps in formal hypothesis testing. Make at least one comment for each step.. . . Steps in Hypothesis Test, Hypothesis Test
# 729 :: 5/23/09	I want to prove that a population mean is not 150. Use an alpha of 5% and set up the full, detailed, five step hypothesis test. Assume when the sampl. . . 1-sample t-test
# 728 :: 5/23/09	What hypothesis testing model (my “models” handout) would be used under each of the following conditions. Use the “model number” from my handout if y. . . Statistical Model, test statistic
# 727 :: 5/23/09	Interpret the following table showing the percentage of individuals on a low-fat or low-cholesterol diet by gender and age. Age Group Women. . .
# 723 :: 5/5/09	Using this research question and data, perform a nonparametric hypothesis test (Part A and B). Research Question: Is the average age greater than 4. . . Sign Test, Mann Whitney
# 722 :: 5/5/09	What is the definition of an "independent" variable? A dependent variable? What about a variable I intend to use to help do some forecasting. Int. . . Scatter Plot, Scatter Diagram, Independent Variable, Dependent Variable
# 721 :: 5/5/09	What does regression do? What is its purpose?. . . Regression Analysis
# 720 :: 5/5/09	City Opera, a local opera company, wishes to take a sample of its subscribers to learn the average number of years people have been subscribing. The d. . . Sample Size
# 718 :: 5/5/09	The state of Texas college admission board has set a standard for automatic acceptances to any university at top 10% of any graduating class will be a. . . Z-Score
# 716 :: 5/5/09	The rockets are playing Lakers tonight in basketball. The lakers average 90 points a game, with a SD of 10. What would the rockets need to score to be. . . Z-Score
# 715 :: 5/5/09	university of texas will accept all students that have a GPA in the top 10% at their school. At yates the school GPA average is 3.0(on a 4.0 scale) wi. . . Z-Score
# 714 :: 5/5/09	The mean score on a math test at milby high school was 50. the standard deviation was 10. If the same test was administered to the entire school distr. . . Z-Score
# 713 :: 5/3/09	Do students at various colleges differ in how sociable they are? Twenty-five students were randomly selected from each of three colleges in a particul. . . ANOVA, Eta-Squared, Effect Size, ANOVA Summary Data
# 712 :: 5/3/09	Make up a scatter diagram with 10 dots for each of the following situations: (a) perfect positive linear correlation, (b) large but not perfect positi. . . Scatter Diagram, Correlation, Curvilinear Correlation
# 711 :: 5/3/09	Four research participants take a test of manual dexterity (high scores mean better dexterity) and an anxiety test (high scores mean more anxiety). Th. . .
# 710 :: 4/30/09	Discuss how the statistical application of Pearson r is used for hypothesis testing. Through application of the Spearman Correlation discuss what typ. . . Correlation, Pearson r, Spearman Correlation
# 709 :: 4/30/09	Discuss which analysis of variance should be applied when an experiment has more than one independent variable. Discuss the assumptions and limitation. . . ANOVA, Factorial ANOVA, 2-Way ANOVA
# 708 :: 4/30/09	Standardized scores offers a way of comparing norm-referenced scores. The z-score distribution is based on knowing how many standard deviations away f. . . Z-Score, t-score, Percentile Rank
# 707 :: 4/29/09	Would you be able to assist me in completing a 5 step hypothesis test on both hypotheses (1 parameter & another with 2 or more)? In completing this t. . . Five Step Hypothesis Testing, Parameter
# 706 :: 4/28/09	What is a chi-squared test used for? What is the typical null and alternate hypothesis when doing a chi-squared test?. . . Chi-Square
# 705 :: 4/27/09	THIS QUESTION IS NO LONGER AVAILABLE. . . 1-sample Z-test
# 703 :: 4/26/09	The following data is a random sample of 1st quiz scores from previous Research 342 classes. 9.5, 6.5, 4.25, 8.5, 7.5, 4.5, 4.25, 6, 7 mean = 6.44 . . . Confidence Intervals
# 702 :: 4/26/09	A random sample of 100 students who took a statistics exam were asked their score on the exam. The mean score on the test was 50; the standard deviat. . . Z-Score, Area between
# 701 :: 4/26/09	A local bakery determines that the probability of a customer ordering a blueberry muffin is 50%. 5 customers come into the bakery. A. What is the pr. . . BINOMDIST, Binomial pmf, Binomial Probability
# 700 :: 4/26/09	2) Assume the following summary statistics, which describe the speed of a computer processor, are available from a sample of Intel Pentium IV chips ma. . . Chebyshev's Theorem
# 699 :: 4/26/09	1) The following are the first Quiz scores from a previous RES 341 class: 9.5, 7.5, 9.5, 7, 10, 7.5, 6.5, 1.5, 8, 10 A. Is this data discrete or co. . . Continuous Data
# 698 :: 4/26/09	A random sample of 10 miniature Tootsie Rolls was taken from a bag. Each piece was weighed on a very accurate scale. The results in grams were 3.087. . .
# 697 :: 4/25/09	A random sample of 30 executives from companies with assets over $1 million was selected and asked for their annual income and level of education. Th. . . ANOVA, Seasonal Data
# 695 :: 4/24/09	I need help with the following. (A) Develop one business research question (B) Formulate a research hypothesis to test one population parameter an. . . Parameter
# 694 :: 4/21/09	Suppose you conduct a study and find that the probability of having a baby boy is 60%. Now suppose three of your relatives are going to have babies. . . .
# 693 :: 4/21/09	Given a single deck of cards, what is the probability of drawing either a king or a diamond? Hint - There are four kings in a deck and 13 diamonds. T. . . Union, Probability, Joint Probability
# 692 :: 4/21/09	Create a Histogram of the following data: Interval Frequency 0 - 5 0 5 - 10 5 10 - 15 5 15 - 20 15 20 - 25 5 25 – . . .
# 691 :: 4/21/09	Calculate the Standard Deviation of the following list of data: 6, 7, 8, 9, 10. . . Standard Deviation
# 689 :: 4/20/09	Accounting procedures allow a business to evaluate their inventory at LIFO (Last In First Out) or FIFO (First In First Out). A manufacturer evaluated. . . Paired t-test
# 687 :: 4/18/09	I would like to determine whether Meijer or Kroger has lower prices on average for families. I randomly speak with 100 customers who are purchasing g. . . Independent Sample
# 686 :: 4/18/09	A label on a container of orange juice claims that the orange juice contains an average of 2 grams of fat with standard deviation of 1.5 grams. A cons. . . 1-sample Z-test
# 685 :: 4/18/09	NKU needs to estimate the mean number of hours that all students work to earn money, on average, per week during the full semesters (fall and spring).. . . Sample Size, Margin of Error
# 684 :: 4/18/09	Tax companies imply that the returns they prepare are perfect, but what proportion of returns from tax companies have mistakes? To answer this questio. . . Confidence Intervals, Confidence Interval around a Proportion
# 683 :: 4/18/09	A baseball fan would like to estimate the mean time it takes to complete a major league baseball game. He randomly selects 40 game lengths (times to c. . . Confidence Intervals
# 682 :: 4/17/09	Explain the difference between testing a single mean and testing the difference between two means. What two assumptions must be met when one is using . . . Difference between means
# 681 :: 4/17/09	If two independent samples are used in a hypothesis test concerning the difference between population means for which the combined degrees of freedom . . . Degrees of Freedom
# 680 :: 4/17/09	To test the null hypothesis that the mean waist size for males under 40 years equals 34 inches versus the hypothesis that the mean differs from 34, th. . . test statistic
# 679 :: 4/17/09	State the null hypothesis, Ho,and the alternative hypothesis, Ha , that would be used to test the claim: The standard deviation has increased from its. . . Null Hypothesis , Alternative Hypothesis
# 678 :: 4/17/09	A particular candidate claims she has the support of at least 60% of the voters in her district. A random sample of 150 voters yields 87 who support h. . . test statistic, Normal Approximation to Binomial
# 677 :: 4/17/09	A random sample of 51 observations was selected from a normally distributed population. The sample mean was x = 88.6 , and the sample variance was s2 . . . Chi-Square, Standard Deviation, Population Standard Deviation, sample variance, sampe standard deviation
# 676 :: 4/17/09	Consider testing Ho: μd ≤ 0 vs. Ha: μd = > 0 with n =20 and t∗ =1.95. Place bounds on the p-value using the table of “critical. . . Student-t, Student’s t-distribution, Critical Value
# 675 :: 4/17/09	A group of sheep, infested with tapeworms, are randomly divided into two groups as follows. Each sheep is assigned a number (1 through 20) and then 10. . . Dependent Sample, Independent Sample
# 674 :: 4/17/09	In what ways is the t distribution similar to the standard normal distribution? In what ways is the t distribution different from the standard normal . . . t-distribution, Standard Normal Distribution
# 673 :: 4/16/09	Classify the following as independent or dependent samples: a. Weights of identical twins b. The effectiveness of two different brands of ibuprofen. . . Dependent Sample, Independent Sample
# 672 :: 4/13/09	In Meijer supermarket, the customer's waiting time to check out is approximately normally distributed with a standard deviation of 2.5 minutes. A samp. . . Hypothesis Test
# 671 :: 4/13/09	A statistician was testing the following hypotheses: Ho: μ = 500 vs. Ha: μ ≠ 500. The p-value approach was to be used. A sample . . .
# 670 :: 4/13/09	Assume that z is the test statistic and calculate the value of z∗ for testing the null hypothesis Ho: μ =150.0 when σ = 4.5, n=15, x(b. . . test statistic, z-test
# 669 :: 4/13/09	You have failed to reject the null hypothesis when it is false, and therefore you have made a A) Type A correct decision. B) Type B corr. . . Type I Error, Type II Error, Hypothesis Test
# 668 :: 4/13/09	Which of the following is the probability of making a Type I error? A) α B) 1 - α C) β D) 1 - β. . . Type I Error, Type II Error
# 667 :: 4/11/09	If the p-value is greater than the level of significance α , then the decision must be to reject Ho. A) True B) False. . . p-value, Hypothesis Test
# 664 :: 4/11/09	If our decision in a hypothesis test is to fail to reject the null hypothesis, then we know that the null hypothesis must be true. A) True . . . Null Hypothesis
# 663 :: 4/11/09	When we reject the null hypothesis, we are certain that the null hypothesis is false. A) True B) False. . . Null Hypothesis
# 662 :: 3/23/09	I need the formula to calculate z-score. My input is: Base Sample Size, Target Sample Size, Base Proportion, Target Proportion. I have a calculator . . . 2-proportion test
# 661 :: 3/19/09	A student is taking a 10 question multiple choice quiz. There are four possible answers to each question. The student decides to guess at random on al. . . BINOMDIST
# 660 :: 3/18/09	Four cards are selected, one at a time, from a standard deck of 52 cards. Let x represent the number of aces drawn in a set of 4 cards. If this expe. . . Binomial Probability
# 659 :: 3/18/09	Suppose that A and B are mutually exclusive events, and that P(A) = 0.4 and P(B) = 0.3. Then, P(A and B) will be: A) 0.0 B) 0.4 C) 0.3 D) 0.7. . .
# 658 :: 3/18/09	Under certain conditions, it is possible that the sum of the probabilities of all the sample points in a sample space is less than one. A) Tru. . .
# 657 :: 3/18/09	If events A and B are not mutually exclusive, they may be either independent or dependent. A) True B) False. . .
# 653 :: 3/11/09	What is the cost of a telephone call (per dollar) using a calling card that follows the formula below for a 20-minute call. Cost = 0.50 + 0.15 Minute. . .
# 651 :: 3/9/09	For a population with a mean of 80 and standard deviation of 12, what is the z-score corresponding to x=71?. . .
# 650 :: 3/9/09	2. Your company makes ice cream (178 flavors!) and has just acquired a distribution company with lots of ice cream trucks. You will use their trucks. . .
# 648 :: 3/7/09	A financial planner wants to compare the yield of income- and growth-oriented mutual funds. Fifty thousand dollars is invested in each of a sample of. . .
# 644 :: 3/3/09	An aptitude test has a mean of 220 and standard deviation of 10. find the corresponding z score for: a) a test score of 232 b) a test score of 212. . . Z-Score
# 642 :: 3/2/09	You are a purchasing agent at a major manufacturing company. You have several hundred business cards from sales reps who have visited you, and you ha. . .
# 641 :: 3/2/09	In general, what is a “Critical Value” or “Cut-Off Score” of a test statistic. . . Critical Value, test statistic
# 639 :: 2/28/09	CherryBerry Soda, Inc. claims that 15 percent of the population can identify its products. In efforts to boost their identity, CherryBerry employs a f. . . Normal Approximation to Binomial , 1-Proportion Test
# 638 :: 2/23/09	To test the null hypothesis that the mean waist size for males under 40 years equals 34 inches versus the hypothesis that the mean differs from 34, th. . . 1-sample t-test
# 637 :: 2/22/09	Hi Jeff thanks for all your help so far, your answers have been great and very timely. It is great to be able have help from someone with great profes. . . Adjusted Wald, Confidence Intervals
# 635 :: 2/22/09	Linemarking for parking bays shall be determined by the retroreflectivity performance of glass beads in the linemarking. The linemarking average level. . . 1-sample t-test, Confidence Intervals
# 634 :: 2/20/09	A contractor is responsible for drainage network cleaning and shall ensure that the required level of service is achieved. The required level of servi. . . 1-Sample Proportion Test
# 633 :: 2/20/09	Roadmarking shall be determined by the retroreflectivity performance of glass beads in the road marking. The roadmarking average level of reflectivity. . .
# 632 :: 2/19/09	An automobile manufacturer wants to estimate the mean gasoline mileage that its customers will obtain with its new compact model. How many sample runs. . . Sample Size, Margin of Error
# 631 :: 2/19/09	My company has been arguing over this topic for quite a while, and I'm looking to put an end to this mathematical question. We are an ad agency who. . . A/B Testing, Response Rates
# 630 :: 2/19/09	Pretend that you are a Finance person in a large dynamic company. Your dream is to become CFO someday, so you want to make good financial decisions. Y. . .
# 629 :: 2/17/09	The following data show samples of three chain stores in three different locations in one town and the amount of dollars spent per customer per visit.. . . ANOVA
# 628 :: 2/16/09	I have a standard normal distribution with Mean 130, Stdev 8 for school X and a normal distribution for 120 and 10 for school Y. If we select 1 studen. . .
# 627 :: 2/16/09	I have two questions. Thanks for answering them. (1)A sports enthusiast created an equation to predict Victories (the team’s number of victories in. . .
# 626 :: 2/15/09	Greetings, My name is Dave Thompson and I work with the Conasauga Drug Court Treatment program in Dalton, GA. I am a Field Practicum Instructor f. . .
# 625 :: 2/11/09	Mean output of solar cells of three types are measured six times under random light intensity over a period of 5 minutes, yielding the results shown. . . . ANOVA
# 623 :: 2/9/09	The following table lists the number of U.S. mainland hurricane strikes (from 1900 to 1996) for various intensities according to the Saffir-Simpson Hu. . . Random Variable, Probability Distribution
# 622 :: 2/9/09	1. If the daily stock price, x, of United Technology is normally distributed with mean 6.56 and standard deviation 2.4, calculate the probability that. . .
# 621 :: 2/8/09	Consider a sample with data values of 10,20,12,17, and 16. Compute the z-score for each of the five observations. . . Z-Score
# 620 :: 2/8/09	The total area under the curve of the standard normal distribution is not necessarily 1.0. A) True B) False. . . Normal Curve, Standard Normal Distribution, Standard Normal Curve
# 619 :: 2/8/09	Suppose the annual consumption of chicken mean is 20.84 pounds per person, and that the standard deviation for the consumption of chicken per person i. . . Central Limit Theorem
# 618 :: 2/8/09	Individual scores of a placement examination are normally distributed with a mean of 84.2 and a standard deviation of 12.8. If a random sample of s. . . Z-Score, t-score
# 616 :: 2/7/09	Evolutionary theories often emphasize that humans have adapted to their physical environment. One such theory hypothesizes that people should spontane. . . 1-sample t-test
# 613 :: 2/7/09	I am confused on how to calculate a z-score. I am doing a six sigma project right now and am lost on doing the z-score. Here is the information I am p. . . Z-Score
# 611 :: 2/5/09	6.) For the following set of data, find the linear regression equation for predicting Y from X: X Y 0 9 . . . Regression Equation
# 600 :: 1/30/09	True or False The moving average method averages out cyclical and irregular components. When using Chi Square , the sum of the expected freque. . . ANOVA, Chi-Square, Goodnees of Fit, F distribution
# 599 :: 1/30/09	There are two major tests of readiness for college, the ACT and the SAT. ACT scores are reported on a scale from 1 to 36. The distribution of ACT scor. . . Z-Score, SAT Scores, ACT Scores
# 597 :: 1/30/09	TRUE OR FALSE 1. ANOVA is used when we want to know if more than two population means are equal. 2. The sum of the squares error measures the vari. . . ANOVA
# 589 :: 1/26/09	Apply the Law of Large Numbers: Explain how the following scenario is possible using a coin toss and fictitious data: As the number of trials increase. . . Law of Large Numbers
# 588 :: 1/26/09	An aptitude test has a mean of 220 and standard deviation of 10. find the corresponding z score for: a) a test score of 232. . . Z-Score
# 587 :: 1/26/09	True or False Generally speaking, the Null Hypothesis is set up for the purpose of either accepting or rejecting it. If the Null Hypothesis is fal. . . Null Hypothesis , Alternative Hypothesis
# 581 :: 1/21/09	hi, I hope you can help me ? I have 30 variables that i wanted to sort them under 5 known groups . the data came from interviews where i collected . . .
# 580 :: 1/21/09	Conduct the equivalent, nonparametric test of hypothesis using the 5-step process. MLB ï¿½ Higher Salaries equate to more home runs per team (Using . . .
# 576 :: 1/16/09	TRUE or FALSE The level of significance is the probability that a true hypothesis is rejected. A Type one error is also referred to as an alpha r. . . Hypothesis Test, Alternative Hypothesis , Alpha, Null Hypothesis
# 574 :: 1/14/09	Assume you have the following data: Ho mu = 200, s = 30, n = 64, and x-bar = 218. Conduct a hypothesis test at the .05 significance level. Assum. . . 1-sample t-test, 1-sample Z-test
# 572 :: 1/13/09	At one university, students are given z-scores at the end of the semester rather than the traditional GPAs. The mean and standard deviation of all stu. . . Empirical Rule, Z-Score
# 571 :: 1/10/09	Dr Zak developed a test to measure depression. He sampled 100 university students to take his five item test. The group of students was comprised of 3. . . Z-Score, Standard Score
# 570 :: 1/7/09	How can a t test be employed in hypothesis testing by the use of directional versus nondirectional hypothesis. . . directional test, 1-tailed test
# 569 :: 12/21/08	Faced with rising fax costs, a firm issued a guideline that transmissions of 10 pages or more should be sent by 2-day mail instead. Exceptions are all. . . 1-sample t-test, TDIST
# 568 :: 12/21/08	16 (a) Plot the data on U.S. general aviation shipments. (b) Describe the pattern and discuss possible causes. (c) Would a fitted trend be helpful? Ex. . . Trend Line, Linear Regression
# 566 :: 12/19/08	In an ANOVA test there are 5 observations in each of three treatments. The degrees of freedom in the numerator and denominator respectively are: a. . . . ANOVA, Degrees of Freedom
# 565 :: 12/19/08	The coefficient of correlation between two variables X and Y was computed to be ƒ{0.60. This means a. the coefficient of determination is 0. b. a. . . Correlation, coefficient of determination
# 564 :: 12/19/08	For each of the following situations, indicate whether an error has occurred and, if so, indicate what kind of error (Type I or Type II) has occurred.. . . Type I Error, Type II Error, Power, Hypothesis Test
# 563 :: 12/19/08	A vinyl siding company claims that the mean time to install siding on a medium-size house is at most 20 hours with a standard deviation of 3.7 hours. . . . 1-sample Z-test, 1-sample t-test
# 562 :: 12/17/08	Why does the main factor MSs in 2 way ANOVA sometimes carry along interaction effect?. . . ANOVA, 2-Way ANOVA
# 560 :: 12/17/08	Throughout history 55% of registered voters actually have cast a ballot. What is the probability that among a group of 28 students who are registered. . . BINOMDIST, Binomial cdf, Compliment Rule
# 559 :: 12/16/08	The serum cholesterol levels for men in one age group are normally distributed with a mean of 185.1 and a standard deviation of 37.8. All units are i. . . Area between, Z-Score
# 558 :: 12/16/08	If Z is a standard normal variable, find the probability that z lies between 0.73 and 1.88 or P(0.73 Area between, Z-Score
# 557 :: 12/16/08	Find the margin or error for the 95% confidence interval used to estimate the population proportion. In a survey of 7100 TV viewers, 38% said they wa. . . Confidence Intervals, Margin of Error
# 555 :: 12/14/08	Complete the following: a. Select a variable. Compare the mean of the variable for a sample of 30 for one group with the mean of the variable for a . . . 2-sample t-test, 2-proportion test, 2-sample z-test, z-test
# 551 :: 12/12/08	Philadelphia is conducting a study on the characteristics of tourists who drive to Eagles football games. Previous studies indicate that approximately. . . Sample Size, Confidence Intervals, Proportion
# 550 :: 12/12/08	Jeff, I am working Trend lines for yearly data and I can't figure this step: trend line is Tt=22.6+0.45 t to generate yearly forecast. Trend line beg. . . Trend Line
# 549 :: 12/10/08	An expert witness in a case of alleged racial discrimination in a state university school of nursing introduced a regression of the determinants of Sa. . . Regression Equation, Regression Analysis
# 548 :: 12/10/08	A researcher used stepwise regression to create regression models to predict BirthRate (births per 1,000) using five predictors: LifeExp (life expecta. . . Stepwise Regression, Regression Analysis
# 546 :: 12/10/08	In the following regression, X = total assets ($ billions), Y = total revenue ($ billions), and n = 64 large banks. (a) Write the fitted regression eq. . . Regression Analysis, Slope, Regression Equation
# 545 :: 12/10/08	In the following regression, X = weekly pay, Y = income tax withheld, and n = 35 McDonald’s employees. (a) Write the fitted regression equation. (b) S. . . Regression Analysis, Slope
# 544 :: 12/10/08	(a) How does correlation analysis differ from regression analysis? (b) What does a correlation coefficient reveal? (c) State the quick rule for a sign. . . Correlation, correlation coefficient , Regression Analysis, significant correlation
# 542 :: 12/9/08	A financial analyst wants to compare the turnover rates, I percent, for shares of oil-related stocks versus other stocks, such as GE and IBM. She sele. . . 2-sample t-test, Unequal Variances
# 541 :: 12/9/08	A stockbroker at Critical Securities reported that the mean rate of return on a sample of 10 oil stocks was 12.6 percent with a standard deviation of . . . F-test, Homogeneity of Variance, Unequal Variances, Levine test
# 540 :: 12/9/08	A sample of 36 observations is selected from a normal population. The sample mean is 21, and the sample standard deviation is 5. Conduct the following. . . 1-sample t-test, 1-tailed test, Null Hypothesis , calculating mean, sample variance, Standard Deviation
# 539 :: 12/9/08	The following sample observations were randomly selected X: 5 3 6 3 4 4 6 8 Y: 13 15 7 12 13 11 9 5 Determine the coefficient of correlati. . . Correlation, coefficient of determination
# 538 :: 12/9/08	When would it be appropriate to use ANOVA and when is it appropriate to use a paired t test? Be specific and give examples.. . . ANOVA, Paired t-test
# 537 :: 12/6/08	Can people really identify their favorite brand of cola? Volunteers tasted Coca-Cola Classic, Pepsi, Diet Coke, and Diet Pepsi, with the results shown. . . 2-proportion test, Chi-Square
# 536 :: 12/6/08	High levels of cockpit noise in an aircraft can damage the hearing of pilots who are exposed to this hazard for many hours. A Boeing 727 co-pilot coll. . . Chi-Square, CHIDIST
# 535 :: 12/6/08	A student team examined parked cars in four different suburban shopping malls. One hundred vehicles were examined in each location. Research question:. . . Chi-Square, CHIDIST
# 534 :: 12/6/08	Sixty-four students in an introductory college economics class were asked how many credits they had earned in college, and how certain they were about. . . Chi-Square, CHIDIST
# 533 :: 12/6/08	I need help on understanding multiple logistic regression, especially inference, goodness-of-fit, and calculating Likelihood Ratio Chi-Square using G^. . .
# 532 :: 12/5/08	Based on the genotypes of parents, offspring are expected to have genotypes distributed in such a way that 25% have genotypes denoted by AA, 50% have. . . Chi-Square, Goodnees of Fit
# 531 :: 12/4/08	What is higher a z score of .500 or a raw score of 17. . .
# 530 :: 12/2/08	What score would it have taken to be in the 90th percentile in a test with a mean of 40 and standard deviation of 7. . . Z-Score, Percent Score
# 528 :: 11/28/08	In a bumper test, three types of autos were deliberately crashed into a barrier at 5 mph, and the resulting damage (in dollars) was estimated. Five te. . . ANOVA
# 527 :: 11/28/08	A sample of 25 concession stand purchases at the October 22 matinee of Bride of Chucky showed a mean purchase of $5.29 with a standard deviation of $3. . . Homogeneity of Variance, F-test, Levine test
# 526 :: 11/28/08	To test the hypothesis that students who finish an exam first get better grades, Professor Hardtack kept track of the order in which papers were hande. . . 2-sample t-test, Homogeneity of Variance, Equal Variances, F-test, Levine test
# 525 :: 11/28/08	Does lovastatin (a cholesterol-lowering drug) reduce the risk of heart attack? In a Texas study, researchers gave lovastatin to 2,325 people and an i. . . 2-proportion test, Normal Approximation to Binomial
# 524 :: 11/24/08	Discuss how t test can be employed in hypothesis testing by the use of directional vs. nondirectional hypotheses. Discuss types of research where usi. . . t-score, Z-Score, directional test, nondirectional test, 1-Sided Test
# 523 :: 11/24/08	Use the given degree of confidence and sample data to construct a confidence interval for the population mean x. Assume that the population has a norm. . . Confidence Intervals, TINV
# 521 :: 11/24/08	The width of a confidence estimate for a proportion will be: a. Narrower for a 99% confidence interval than for a 95% confidence interval. b. Wider . . . Confidence Level, Confidence Intervals, Proportion
# 520 :: 11/23/08	Your company asks you to compare a new advertising campaign and the old one. Sample data on the accounts as follows: Old: 40, 28, 35, 38, 31, 42, 26,. . . Confidence Intervals, Median, Mode, mean, t-statistic, Standard Error of the Mean
# 519 :: 11/23/08	Fill in the P (X=x) values in the table to give legitimate probability distribution for the discrete random variable X, whose possible values are -4, . . . Random Variable, Probability, Compliment Rule
# 517 :: 11/22/08	An executive drives his vehicle from home to work daily. Driving times are normally distributed with a mean of 35 minutes and standard deviation of 8. . . Z-Score, Area between, above .10
# 516 :: 11/19/08	Given a mean score of 70, standard deviation of 15,percentile of 23.Find the Z score,T score and raw score. Please explain how to work backward on a . . . T score, Percent Score, Z-Score
# 515 :: 11/19/08	I run various A/B Split tests online. I always set all my tests for 10,000 visitors so page A and B are each equally rotated 5,000 times. My problem. . . 2-proportion test, Normal Approximation to Binomial , Power, A/B Testing
# 514 :: 11/17/08	I am trying to assess the impact of an event on a population. I ran a survey before the event and then I ran the survey after the event. The collect. . . Paired t-test, Within Subjects, 1-Sided Test, One-Tailed Test
# 513 :: 11/17/08	I have a question about SEYhat in time-series regression for N=1 subject.... I want to know whether the StdError of the fitted score (SEYhat) can. . . Time-Series, Regression Analysis, autocorrelation
# 512 :: 11/14/08	When estimating the mean of a population, how large must the sample be in order that the 95% error margin is 1/8 the standard deviation?. . . Sample Size, Margin of Error, Standard Deviation, Standard Error of the Mean
# 511 :: 11/13/08	A machine produces 3 inch nails. A sample of 100 nails is selected, and it is found that 25 are shorter than 3 inches. Find the 95% confidence interv. . . Proportion, Confidence Intervals, One-Tailed Area
# 510 :: 11/13/08	Survey to determine what proportion of new car buyers continue to have their car serviced at the dealership after warranty ends. Estimates 30% of cust. . . Sample Size, Confidence Level
# 509 :: 11/13/08	A researcher expects the population proportion of the Cubs Fans in Chicago to be 80%. Error of less than 5% confident of an estimate to be made from a. . . Confidence Intervals, Sample Size, Margin of Error
# 508 :: 11/13/08	In a national wide survey a researcher expects 30 percent of the population will agree with an value statement. He wishes to have less than 2% error a. . . Sample Size, Margin of Error, Confidence Level
# 507 :: 11/12/08	In a survey of 500, 60% responded positively to an value question. Calculate a confidence level at 95% to get an interval estimate for proportion?. . . Sample Size, Confidence Intervals, Proportion
# 506 :: 11/12/08	Suppose you are planning a sample of employees to determine the monthly average # of vacation days. Standards set: Confidence level of 99% and an erro. . . Sample Size, Margin of Error, Confidence Intervals
# 505 :: 11/11/08	Calculate a 98% confidence interval for the following data 15.7,15.7,15.5,15.2,15.2,15.1,15.3.. . . Confidence Intervals, TINV, Margin of Error, t-statistic
# 504 :: 11/9/08	Calculate the 95% confidence interval on the following GPA's from 30 randomly selected students. 0.979 0.891 0.962 0.858 0.909 0.936 0.963 0.9. . . Confidence Intervals, Margin of Error, t-statistic
# 503 :: 11/7/08	Choose a variable and collect data for at least three different groups (samples). Compare the means of the three groups using the one-way ANOVA techni. . . ANOVA, F-statistic
# 502 :: 11/7/08	Administrative staff based at a business school in the UK are advised to take a 15 minute break from their personal computer after working on it for 9. . . Confidence Intervals, TDIST, t-test, Z-Score
# 501 :: 11/7/08	In a survey of adults, 68% thought that DNA test for identifying an individual were very reliable. You randomly select 24 adults and ask each if he or. . . BINOMDIST, Binomial Probability, Continuity Correction, Normal Approximation, Normal Approximation to Binomial
# 500 :: 11/7/08	In a recent year grade 8 Washington State public school students taking a mathematics assessment test had a mean score of 276.1 with a standard deviat. . . Percent Score, Area between, Z-Score
# 499 :: 11/7/08	A newspaper finds that the mean number of typographical errors per page is five. Find the probability that: a. Exactly five typographical errors will. . . Poisson, Poisson Distribution
# 498 :: 11/7/08	During the next hour, five customer arrivals are expected. What is the probability that more than five customers will show up (according to the Poisso. . . Poisson, Poisson Distribution
# 497 :: 11/6/08	A random sample of n=64 children of working mothers showed that they were absent from school an average of 5.3 days per term, with a standard deviatio. . . Confidence Intervals, Confidence Level
# 495 :: 11/4/08	The EPA range for a car is 20-28mpg, how large of a sample would be required to estimate your mean mpg with an error of +/- 1 mpg with 90% confidence. . . Sample Size
# 494 :: 11/4/08	If the average price of a new home is 145,000 what is the minimum and maximum prices of the houses a contractor will need to build to include the midd. . . Z-Score, Area between
# 493 :: 11/4/08	On a police sergeants exam, the historical mean scored was 80 with a standard deviation of 20. Four offiers scored 195,175,191, and 189 respectively. . . . Empirical Rule, Z-Score, Unusual Event, Percent Score
# 492 :: 11/3/08	if an eligible couple on an average has 3.3 children then the birth rate will be?. . .
# 491 :: 10/30/08	Using continuity Correction. There are many situations in which a normal distribution can be used as a good approximation to a random variable that ha. . . Continuity Correction
# 487 :: 10/28/08	Find a confidence interval for the mean assuming that each sample is from a normal population. Mean = 127, s = 27, n = 16. Find the 90% Confidence Int. . . TINV, t-distribution, Confidence Intervals
# 486 :: 10/28/08	1.A telescope manufacturer wants its telescopes to have standard deviations in resolution to be significantly below 2 when focusing on objects 500 lig. . .
# 485 :: 10/27/08	Assume that the heights of 5 year old boys are normally distribued with a mean of 100cm and a standard deviation of 60. What is the sampling distribut. . . TINV, Confidence Intervals, Standard Error of the Mean, Standard Deviation of the Mean
# 484 :: 10/25/08	With a normal distribution of 50 and standard deviation of population =10, how do I figure out the score at the 40th percentile? How do I figure out t. . . Z-Score, Area between, Percent Score
# 483 :: 10/21/08	I have a research study where we have a "test" and a "control" group. We calculated a market share percentage for both groups, the test group was in . . . McNemar Chi-Square , Chi-Square
# 482 :: 10/20/08	a telescpoe manufacturur wants its telescopes to have standard deviations in resolution to be significantly below 2 when focusing on objects 500 light. . .
# 481 :: 10/20/08	a centre university has a student population of 60000. the university is interested in determining what proportion of them is in favour of a new gradi. . .
# 476 :: 10/13/08	Does normal distribution is something to do with Altman Z-Score?. . . Altman Z-Score, Z-Score
# 475 :: 10/12/08	A telephone manufacturer wants its telescope to have standard deviation in resolution to be significantly below 2 when focusing on object 500 light-ye. . . Standard Deviation, Chi-Square, Chi-Square Distribution
# 474 :: 10/12/08	The central university has a student population of 60000. The university is interested in determining what proportion of them is in favour of a new gr. . .
# 471 :: 10/9/08	A central university has a student population of 60,000. The university is interested in determining what proportion of them is in favour of a new gra. . . Margin of Error, Confidence Intervals, Sample Size
# 470 :: 10/9/08	A telescope manufacturer wants its telescopes to have standard deviations in resolution to be significantly below 2 when focusing on objects 500 light. . . Chi-Square Distribution, Confidence Intervals, Standard Deviation, Variance
# 469 :: 10/8/08	Mean output of solar cells of three types are measured six times under random light intensity over a period of 5 minutes, yielding the results shown. . . .
# 467 :: 10/7/08	The Web-based company Oh Baby! Gifts has a goal of processing 95 percent of its orders on the same day they are received. If 485 out of the next 500 o. . . 1-Proportion Test, Normal Approximation
# 466 :: 10/7/08	Biting an unpopped kernel of popcorn hurts! As an experiment, a self-confessed connoisseur of cheap popcorn counted 773 kernels and put them in a popp. . .
# 465 :: 10/7/08	A sample of 20 pages was taken without replacement from the 1,591-page phone directory Ameritech Pages Plus Yellow Pages On each page, the mean area d. . .
# 464 :: 10/7/08	How do you know when to use a t-score instead of a z-score and vice versa?. . . Z-Score, t-score
# 463 :: 10/6/08	Find the probability of correctly answering the first 2 questions on a multiple choice test if random guesses are made and each question has 3 possibl. . . Multiplication Rule
# 462 :: 10/6/08	Olympic Track related question: You know the last 5 race times at the same distance for 8 runners competing in a race. As such, you can calculate the. . . Z-Score
# 461 :: 10/6/08	My question is on Measurement system analysis (MSA). My metric is lead time. I calculated it from the system (computer database) which stores all th. . . Gage R&R
# 460 :: 10/5/08	20% kids danced. If 10 were selected at random, find probability that exactly four danced.. . . BINOMDIST, Binomial pmf
# 459 :: 10/5/08	How do you calculate a participant score if she was at the 67th percentile? I only have the standard deviation of the population and the mean. s = 27 . . . Percent Score, Percentile, Z-Score
# 458 :: 10/5/08	In 1992, the FAA conducted 86,991 pre-employment drug tests on job applicants who were to be engaged in safety and security-related jobs, and found th. . . Confidence Intervals, Normality Assumption
# 457 :: 10/4/08	What is a simple but legitimate power analysis formula? I am trying to do qualitative research on African American HS boys in the Midwest. I am using . . .
# 456 :: 10/4/08	I am trying to find out if a difference between two response sets is significant. I asked 98 boys what modalities they thought were attractive to girl. . . 2-proportion test
# 455 :: 10/4/08	Assume scores are normally distributed with a mean of 10 and std dev of 2. Find the first quartile Q1, which is the score separating the bottom 25% fr. . . Quartile
# 454 :: 10/4/08	what concerns arise from using formulae to calculate standard scores. . .
# 453 :: 10/4/08	A central university has a student population of 60,000. The university is interested in determining what proportion of them is in favour of a new gra. . . Sample Size, Margin of Error
# 452 :: 10/3/08	why does a z score always have a mean of 0 and a standard deviation of 1?. . . Standard Normal Curve
# 451 :: 10/3/08	A sample of the math test scores of 35 fourth-graders has a mean of 82 with a standard deviation of 15. Find the 95% confidence interval of the mean. . . Confidence Intervals, Confidence Level
# 450 :: 10/3/08	A researcher is interested in estimating the average salary of fire fighters in a large city. He wants to be 95% confident that his estimate is correc. . . Margin of Error, Sample Size
# 447 :: 10/2/08	If he correlaion between X and Y is equal to -1.0, what do we know about the prediction of Y by X? (a)It's negative (b) It's postive (c)It's perfect (. . .
# 446 :: 10/2/08	When using two predictor variables, these variables should be (a)Correlated (b)Related (c)Independent (d) Dependent. . .
# 445 :: 10/2/08	What must be used to examine an outcome that is predicted from two independent variables? (a)Multivariate regression (b)Multiple regression (c)Simple . . .
# 444 :: 10/2/08	What mut be done to categorical variables in order to use them in a regression analysis? (a)Nothing (b)Dummy coding (c)Problem coding (d)Categorical c. . .
# 443 :: 10/2/08	A postive trend line is associated with what type of slope? (a)Negative slope (b)Direct slope (c)Postive slope (d)Nondirectional slope. . .
# 442 :: 10/2/08	Using the regression Formula with slope=.704 and intercept=.719, what would the predicted college GPA be for a student whose current high school GPA=3. . .
# 441 :: 10/2/08	Which of the following Excel Function calulated the point at the regression line crosses the y-axis (a)SLOPE (b)CORREL (c)INTERCEPT (d)PEASON. . .
# 440 :: 10/2/08	How would you represent score of Y based on a known value of X? (a)Y (b)y-intercept (c)Y'(d)Y=Xa. . .
# 439 :: 10/2/08	I have a jar containing 100,000 marbles. There are 6 colors of marbles in the jar and they are present at frequencies of 2%, 2%, 4%, 10%, 57%, 25%. . . .
# 438 :: 10/2/08	How do i compute for the standard score (z-score)of the following data? How will the graph look like? 53 53 50 45 45 43 42 42 41 40 39 39 . . .
# 437 :: 10/1/08	how can i interpret standard or z scores?. . .
# 436 :: 10/1/08	when is ecological correlation appropriate? When is it not useful?. . . Ecological correlation
# 435 :: 10/1/08	Parametric and Nonparametric Data Identification Assignment Label each of the following situations “P” if it is an example of parametric data or “NP”. . . Non-Parametric, Parametric
# 433 :: 10/1/08	My data set is non-normal (cycle time). Can I convert the data into "Good and Bad" based on a specification and then find a Z value to estimate my sig. . . Cycle Time, Non-Normal Data, Log Transformation
# 432 :: 9/30/08	Assume that the population of heights of male college students is approximately normally distributed with mean m of 68 inches and standard deviation s. . . TDIST, t-score
# 430 :: 9/29/08	Individual scores of a placement examination are normally distributed with a mean of 84.2 and a standard deviation of 12.8. If the score of an indi. . .
# 429 :: 9/29/08	A coin was flipped 60 times and came up heads 38 times. (a) At the .10 level of significance, is the coin biased toward heads? Show your decision rule. . . Normal Approximation to Binomial , 1-Proportion Test
# 428 :: 9/29/08	Each student in an experiment was told to look at 100 cars and count the number of people wearing the seat belts. The mean score for the class was fou. . . Z-Score
# 427 :: 9/29/08	Set up a model to test whether there are differences in mean ... DATA SET E Ages and Weights of 31 Randomly Chosen U.S. Nickels (n = 31 nickels) Nicke. . .
# 426 :: 9/29/08	can individual scores of a 542 student be converted into percentage and fed into spss for anova and tukey test. . . Percent Score, ANOVA
# 425 :: 9/29/08	A real estate agent has 2 tours. The first tour through N1and has 10 homes for sale, whereas the second tour through N2and has 5 homes for sale. The r. . .
# 424 :: 9/29/08	A recent article in a computer magazine suggested that the mean time to fully learn a new software program is 40 hours. A sample of 100 first-time use. . . 1-sample t-test, Alternative Hypothesis , Null Hypothesis , test statistic, p-value
# 423 :: 9/28/08	the lengths of human pregnancies are normally distributed with a mean of 268 days and a standard deviation of 15 days. What is the probability that a . . . Z-Score
# 422 :: 9/28/08	A newspaper finds that the mean number of typographical errors per page is five. Find the probability that: 1. Exactly five typographical errors wi. . .
# 421 :: 9/28/08	A surgical technique is performed on eight patients. You are told that there is an 80% chance of success. Construct a binomial distribution. Find. . .
# 420 :: 9/28/08	In one region, the September energy consumption levels for single-family homes are found to be normally distributed with a mean of 1050 kWh and a stan. . . Z-Score
# 419 :: 9/28/08	Suppose two events are independent. One event has probability of 0.25, while the other has probability of 0.59.. . . Multiplication Rule
# 418 :: 9/27/08	Dear Stats Person, Here is my question. If a person were to guess a number from 1-10, the chance of guessing a 4 would be 0.1. If 5 people were a. . . BINOMDIST, Binomial Probability, Binomial pmf
# 417 :: 9/27/08	Could you detail the value of using standard scores (Z scores) to compare relative performance of individual test scores.. . . Z-Score
# 416 :: 9/27/08	Twenty students randomly assigned to an experimental group receive an instructional program; 30 in a second group do not. After 6 months, both groups . . . 2-sample t-test, Hypothesis Test
# 415 :: 9/27/08	how do i find the lower 25% and upper 75% and the interquartile range. . . Interquartile Range
# 414 :: 9/27/08	If you have 100 respondents identifying their gender, what would be the expected frequency for each category? a)25 b)50 c)75)d)100. . .
# 413 :: 9/27/08	In order to meet the sample assumption associated with parametrics statistics, how many subjects do you need? a)20 b)30 c)50 d)100. . .
# 412 :: 9/27/08	If you have 30 espondents identifying their political preference(i.e.,Democrat, Republican, Independent),what would be the expected frequency for each. . .
# 411 :: 9/24/08	Do you have any hints how I can figure out critical values at the significance level? Can you figure this out in excel or megastat? Is there a equat. . . NORMSINV, TINV
# 410 :: 9/24/08	You take a random sample of pizzas sold during a one hour period over the next week. Group 1 and Group 2 The results are shown in the table to the a. . . 2-sample t-test
# 409 :: 9/24/08	What is the height of a man with the z score of -1.7?. . . Z-Score
# 408 :: 9/23/08	Use Excel, or MINITAB to fit the regression model, including residuals and standardized residuals: DATA SET E Ages and Weights of 31 Randomly Chose. . . Minitab, Regression Analysis, Residuals
# 405 :: 9/22/08	Marge and Joe have five daughters. They decide to have another baby because they are sure the next one will be a boy (after all, what are the odds of . . . BINOMDIST, Multiplication Rule, Gambler's Fallacy, Probability Mass Function
# 404 :: 9/22/08	How do you calculate a standard deviation when your data is so large you can not enter it into the calculator. (I have 50 pcs of data). . .
# 403 :: 9/22/08	Based on information obtained from a sample of 54, a 98% confidence interval for the average profit level of regional banks is given by 67.4 million t. . . Standard Deviation, Margin of Error, Critical Value, Confidence Intervals, Confidence Level
# 402 :: 9/21/08	How can I compute a one-sided 97.5% confidence interval using SPSS for this ? IN a cohort of 121 eyes treated with drug A, 3 eyes experience a drug . . . SPSS, Confidence Intervals, 1-sided Interval
# 401 :: 9/20/08	A woman wrote to DearAbby and claimed that she gave birth 308 days after a visit from her husband, who is in the Navy. Lengths of pregnancies have a . . . Z-Score, Unusual Event
# 400 :: 9/20/08	What is the standard general score conversion formula? Is this the same as a z-score formula? Which leads me to ask How do you convert from one standa. . . Standard Score
# 399 :: 9/20/08	When you calculate CIs for time on task, I notice that you use the critical value from the t-distribution (TINV(0.05, degrees_of_freedom)). But when y. . . exact interval, Binomial Probability, TINV, Adjusted Wald, Wald Interval, Normal Approximation, Small Sample
# 398 :: 9/19/08	What is the formula for the exclusive range? What is the formula for the inclusive range?. . .
# 397 :: 9/19/08	mean score 100,standard deviation 20, z score-5 , what is the raw score?. . . Z-Score, Raw Score from Z-score
# 396 :: 9/19/08	what is the bottom of 20% of SAT. . .
# 395 :: 9/19/08	What is the Variance, Standard Deviation and Range of the following set of scores? 20,24,26,22,18,16,18 and then 10,15,12,18,19,16,12. . .
# 391 :: 9/18/08	An engineer in an automotive factory wishes to know what the tire pressure is on all cars leaving the factory. She measures the tire pressure on a sa. . . Standard Error of the Mean, t-statistic, Confidence Intervals, Critical Value
# 390 :: 9/18/08	How do you find the normal distribution when the mean is 50 witha standard deviation between scores of 32 and 47?. . . Area between, Z-Score
# 389 :: 9/18/08	How do you dertermine a z-score for continuous data?. . . Z-Score
# 388 :: 9/17/08	In Dallas, some fire trucks were painted yellow (instead of red) to heighten their visibility. During a test period, the fleet of red fire trucks made. . . 2-proportion test, Binomial Probability, Normal Approximation
# 386 :: 9/17/08	I am calculating the effectiveness of an educational intervention using a pretest-posttest design. I plan to run an ANCOVA on the scores with the pret. . . Covariate, ANCOVA, ANOVA
# 385 :: 9/16/08	Given that the traveling distance for a population of college students is normally distributed with the mean of 10 kilometers and standard deviation e. . . Z-Score
# 384 :: 9/16/08	Test at the 5% level of significance whether the true mean time it takes for luggage to reach the travelers is less than 17 minutes. Determine the nul. . .
# 383 :: 9/15/08	Briefly describe the concept of a confidence interval and provide an example.. . . Confidence Intervals
# 381 :: 9/13/08	If I know the T-score for those who made an A on a test is 60, the z-score for those that made a B is .5, the number of students total is 200, how can. . . Z-Score
# 380 :: 9/11/08	What is the relationship between the sign of the correlation coefficient and the sign of the slope of the regression line?. . . Correlation, Regression Line
# 379 :: 9/11/08	1 a. with a mean of 300 and a standard deviation of 80, how high a score do you need to be in the top 30%? 1 b. What is the interquartile range for. . . Interquartile Range, Z-Score
# 378 :: 9/10/08	We have administered an anxiety test to all members of the class. The mean anxiety score is 71 and the standard deviation is 9. (higher score=higher a. . . Z-Score
# 377 :: 9/10/08	A sample of households that subscribe to the United Bell Phone Company revealed the following numbers of calls received by each household last week. D. . . mean, Median, Standard Deviation
# 376 :: 9/10/08	What statistical tests can I perform to compare two groups asked the same question, when the question has a yes/no answer and the sample groups are di. . . 2-proportion test
# 375 :: 9/9/08	why are histograms more appropate than bar graphs. . .
# 374 :: 9/9/08	A sample of size n = 14 is selected from a normal population to construct a 95% confidence interval estimate for a population mean. The interval was c. . .
# 372 :: 9/8/08	Can you please direct me to a site that would have an illustration of the normal curve that also includes cumulative percentiles, Z-score equivalents,. . . SAT Scores, Normal Curve
# 371 :: 9/8/08	Can you give me a formula to calculate sample size?. . . Sample Size, Margin of Error
# 370 :: 9/6/08	The accounting department at Weston reports that it takes two construction workers a mean of 32 hours and a standard deviation of 2 hours... Determin. . . Area between, Z-Score
# 369 :: 9/5/08	A random sample of 10 miniature Tootsie Rolls was taken from a bag. Each piece was weighed on very accurate scale. The results in grams were 3.087 3.. . . Margin of Error, Sample Size, Confidence Intervals
# 368 :: 9/5/08	in a random sample of 200 person of a town 120 are found to the tea drinker.In a random sample of 500 person of another town 240 are found to be tea d. . . Normal Approximation, 2-proportion test, Binomial Probability
# 367 :: 9/5/08	find the area under standard normal curve which lies (a) to the right of Z=1.76,(b)to the left of Z=.94,(c)to the right of Z=-.65,(d)b/w Z=.34 & Z=.62. . . Area between, Z-Score
# 366 :: 9/4/08	If I have 3 tables in the classroom with 16 girls and 8 boys in the class, what are the chances of 8 girls sitting at one table when seats are assigne. . .
# 364 :: 9/4/08	A sample of 20 pages was taken without replacement from the 1,591-page phone directory Ameritech Pages Plus Yellow Pages. On each page, the mean area . . . Margin of Error, Confidence Intervals, Sample Size
# 362 :: 9/1/08	Popcorn kernels take between 100 and 200 seconds to pop. What sample size (number of kernels) would be needed to estimate the true mean seconds to pop. . . Small Sample, Sample Size, Margin of Error, Confidence Intervals
# 361 :: 8/30/08	If I have a formula that predicts the winners of football games and it picked 600 out of 20000 games with 70% of the 600 being winners how can I estim. . .
# 360 :: 8/27/08	What does a negative z-score represent? eg. -0.381. . .
# 359 :: 8/27/08	You have a normal distribution and your subject has a z score = 0. What percentage of the group will be below your subject?. . .
# 358 :: 8/25/08	In the same set of data,can two or more elements have the same z score.. . . Z-Score
# 357 :: 8/25/08	Biting an unpopped kernel of popcorn hurts! As an experiment, a self-confessed connoisseur of cheap popcorn carefully counted 773 kernels and put them. . . Confidence Intervals, Normal Approximation to Binomial , Proportion
# 356 :: 8/24/08	The mean weight of 500 students is 151 lbs and the standard deviation is 15 lbs. Assuming the weights are normally distributed, find out how many stu. . . Area between, Z-Score
# 355 :: 8/20/08	If Range = (6 * Standard Deviation), can it be concluded that Data is normal. . . Nomal Distribution, Probability Plot
# 354 :: 8/20/08	A random sample of 10 miniature Tootsie Rolls was taken from a bag. Each piece was weighed on a very accurate scale. The results in grams were 3.0. . . t-statistic
# 353 :: 8/19/08	A surgical technique is performed on eight patients. You are told that there is an 80% chance of success. a) Construct a binomial distribution. . . . BINOMDIST, Binomial Probability
# 351 :: 8/17/08	As an experiment, a self-confessed connoisseur of cheap popcorn carefully counted 773 kernels and put them in a popper. After popping, the unpopped ke. . . Confidence Intervals
# 350 :: 8/16/08	A robot, when working properly, produces 5% or less defective items. whenever the robot produces more than 5% defective items, i needs repair. A rando. . . Continuity Correction, Normal Approximation, binomial, 1-Sample Proportion Test
# 349 :: 8/15/08	A bank has determined that the monthly balances of savings accounts of its customers are normaly distributed with an average balance of $1200 and stan. . . Z-Score
# 348 :: 8/15/08	A random variable X is normal distributed with a mean of 250 and standard deviation of 50. Given that X = 175, what is its corresponding z-score? Rou. . . Z-Score
# 347 :: 8/14/08	Why is population shape of concern when estimating a mean? What does sample size have to do with it?. . .
# 346 :: 8/14/08	Why is population shape of concern when estimating a mean?. . .
# 345 :: 8/14/08	What are the 5 steps involved in hypothesis testing using the traditional/classical method; Can you use a simple real world example to explain it to m. . . Null Hypothesis , Alternative Hypothesis , Hypothesis Test, Steps in Hypothesis Test
# 344 :: 8/14/08	Explain the difference between testing a single mean and testing the difference between two means. What two assumptions must be met when one is using . . . Standard Deviation, z-test, Normally Distributed, Homogeneity of Variance
# 343 :: 8/13/08	The following data show samples of three chain stores in three different locations in one town and the amount of dollars spent per customer per visit.. . . ANOVA
# 342 :: 8/13/08	In a one-way ANOVA, there are three treatments with n1 = 5, n2 = 6 and n3 = 5. The rejection region for this test at the 5% level of significance is__. . . ANOVA, F-statistic
# 340 :: 8/12/08	Hi Jeff, You have lots of great info on your site; thanks! However, I'm trying to reconcile some different items and they seem to disagree. Can you. . .
# 339 :: 8/12/08	My question is really about sample size. Say you work at a facility and want to perform an assessment of your safety culture – this would involve mul. . . Sample Size, Margin of Error
# 338 :: 8/11/08	Is the chi-square distribution is a skewed distribution whose mean value is n for degrees of freedom larger than two?. . . Chi-Square
# 337 :: 8/11/08	is the chi-square distribution used for inferences about the population mean when the standard deviation is unknown?. . . Chi-Square
# 336 :: 8/11/08	Why is population shape of concern when estimating a mean? What does sample size have to do with it?. . . Central Limit Theorem
# 335 :: 8/10/08	The random variable x has the following probability distribution. x 1 2 3 4 5 P(x) 0.5 0.2 0.1 0.1 0.1 Find the mea. . . Expected Value, Random Variable, Standard Deviation
# 334 :: 8/10/08	find the z value so that 20% of the standard normal curve lies to the right of Z. . . Z-Score
# 333 :: 8/10/08	A woman sells an average of 300 books per month, with a standard deviation of 50. Over the next ten years, how many months will she sell more than 375. . . Z-Score
# 332 :: 8/10/08	If our decision in a hypothesis test is to fail to reject the null hypothesis, then do we know that the null hypothesis must be true?. . . Null Hypothesis
# 331 :: 8/10/08	When we reject the null hypothesis, we are certain that the null hypothesis is false ?. . . Null Hypothesis
# 330 :: 8/9/08	If you had a sample size of 50 and did not know the standard deviation of the population, would you use a t or a z statistics in your analysis? Why?. . . t-test, z-test
# 329 :: 8/8/08	A husband and wife make their decisions independently of each other, and then they compare their decisions. If they agree, the decision is made; if th. . . Multiplication Rule
# 327 :: 8/8/08	Want a sample size of about 60 (30 controls and 30 cases). At 5% significance and 80% power.How do i determine the standard deviation and mean differe. . . Power, Standard Deviation, Mean Difference
# 326 :: 8/7/08	What statistic would be applied if the independant variable is nominal and one dependant variable is nominal and one dependant variable is scale? Is t. . . t-test
# 325 :: 8/7/08	A doctor knows from experience that 20% of the patients to whom he gives a high blood pressure drug will have undesirable side effects. Assume the doc. . . BINOMDIST, Excel, Binomial Probability
# 322 :: 8/7/08	What effect does an increase in the level of confidence have on the width of the confidence interval?. . . Confidence Level
# 321 :: 8/7/08	A normal distributed population has a mean of 250 pounds and a standard deviation of 10 pounds. Given n = 20, what is the probability that this sample. . . Area between
# 320 :: 8/6/08	Individual scores of a placement examination are normally distributed with a mean of 84.2 and a standard deviation of 12.8. If the score of an indi. . . t-score, TDIST
# 319 :: 8/6/08	A machine cuts circular filters from large rolls of material. If 7.3% of the filters fail to meet specifications, use the normal approximation to the . . . binomial, Binomial Probability, Normal Approximation, Continuity Correction
# 318 :: 8/6/08	A traffic study at one point on an interstate highway shows that vehicle speeds are normally distributed with a mean of 61.3 mph and a standard deviat. . . Area between, Z-Score
# 317 :: 8/5/08	Can the bell curve probability value be over the value of 1?. . . Normal Curve, Bell Curve
# 316 :: 8/5/08	Hello, I work in Aerospace Engineering. Aerospace components are often subjected to cyclic loads and can fail in "fatigue". The designers design the p. . . Sigma Level
# 315 :: 8/5/08	An engineer in an automotive factory wishes to know what the tire pressure is on all cars leaving the factory. She measures the tire pressure on a sa. . . Standard Error of the Mean, Standard Deviation, Confidence Intervals, Critical Value, t-statistic
# 314 :: 8/5/08	I am doing A/B testing on an ecommerce web site. I have been working on rule of thumb of 500 vistors through each page or 50 conversions on one of the. . . 2-proportion test, A/B Testing
# 313 :: 8/5/08	3 methods, A, B, and C are available for teaching a certain industrial skill. Only one of these methods is used in teaching a particular worker. The f. . . Bayes Theorem , Conditional Probability, Addition Rule
# 311 :: 8/4/08	A random sample of 100 pumpkins is obtained and the mean circumference is found to be 40.5 cm. Assuming that the population standard deviation is know. . . p-value, Null Hypothesis , Alternative Hypothesis , Z-Statistic, t-statistic
# 310 :: 8/4/08	Various temperature measurements are recorded at different times for a particular day. the mean of 20 degrees C is obtained for 40 temperatures on 40 . . .
# 309 :: 8/4/08	A cereal company claims that the mean weight of the cereal in its packets is 14 ounces. The weights in ounces of the cereal in a random sample of 8 of. . . 1-sample t-test, TDIST, t-score, t-statistic
# 305 :: 8/2/08	How do I determine what test statistic to use if given a sample of test scores for a present year and a previous year using a .05 significance level t. . . Continuous Data, Discrete Data, Null Hypothesis
# 304 :: 8/1/08	Is a number whose z score is equal to zero equal to the mean?. . .
# 303 :: 8/1/08	This question was put to me the other day; Whats the Z-score of 100? my reply no enough info without the standard deviation or the mean I cannot calcu. . .
# 301 :: 7/31/08	What is the advantage of a t-score over a z-score?. . . t-statistic, t-score
# 299 :: 7/30/08	random variable x is normally distributed with mean of 250 and standard deviation of 50 find z-score for x=175. . . Z-Score
# 298 :: 7/29/08	a sample of 50 men with a mean of 35 and sd of 3.2 and alpha of .05, what is the z score, the critical value, the test value. . .
# 297 :: 7/28/08	What is the formula for finding the t-statistic. . . Newton-Raphson, t-statistic
# 296 :: 7/28/08	What is the Z value that corresponds to a probability of .05?. . .
# 295 :: 7/28/08	How can I calculate a Z score with only the mean and the standard deviation?. . . Z-Score
# 294 :: 7/28/08	A test is normally distributed with a mean of 40 and a standard deviation of 7. (a) What score would be needed to be in the 85th percentile?. . . Z-Score, Percentile, Percentile Rank
# 293 :: 7/28/08	How can you use a Z score to interpret data in a school. . . Z-Score
# 291 :: 7/26/08	According to the standard normal curve, _____% of values should fall; within +/ – 1 standard deviation(s) from the mean; +/- 3 standard deviation. . . Standard Normal Curve, above .10
# 289 :: 7/25/08	A standard I.Q. test produces normally distributed results with a mean of 100 and a standard deviation of 15. If an average I.Q. is defined to be any . . . Z-Score, IQ Score
# 288 :: 7/24/08	Twenty-seven users completed a task, and each user did so with a combination of two variables, S and V, which can each have a value of "yes" or "no". . . . Newton-Raphson, Logistic Regression, Maximum Likelihood
# 287 :: 7/23/08	in a study of 11000 car crashes it was found that 5720 of them occurred within 5 miles of home. use a 0.01 significance level to test tha claim that m. . . Binomial Probability, binomial, BINOMDIST
# 285 :: 7/20/08	A company is filling bags of rock salt to a level of 50 pounds. It believes that all bags are filled correctly, but would like to use a hypothesis tes. . .
# 283 :: 7/19/08	The lengths of pregnancies are normally distributed with a mean of 264 days and a standard deviation of 25 days. If 100 women are randomly selected, f. . . Z-Score, Area between
# 282 :: 7/16/08	In normal distribution with mean 55 and atandard deviation 10,the area to the right of 55 is a) 0.6 b) 0.8 c) 0.9 d) 0.75. . .
# 281 :: 7/16/08	in a normal distribution curve with mean as 55 and standard deviation as 10 what will be the area on the right side of the curve and how?. . .
# 280 :: 7/16/08	In normal distribution with mean 55 and atandard deviation 10,the area to the right of 55 is a) 0.6 b) 0.8 c) 0.9 d) 0.75. . .
# 278 :: 7/15/08	out of a random sample 167 students pass an exam out of the 300. how do you calculate an exact 99% confidence interval for the proportion of sudents w. . . exact interval, Confidence Intervals
# 277 :: 7/14/08	If an A is given to a student who scores 90% or above, what would the minimum z-score be for a 300 multiple choice question test with a mean of 195 an. . . Z-Score
# 276 :: 7/11/08	Why is population shape of concern when estimating a mean? What does sample size have to do with it?. . . Normally Distributed
# 275 :: 7/11/08	The lowest 25% of the normal distribution falls below what z-score and t-score. . . T score, Z-Score
# 273 :: 7/10/08	Discuss the characteristics of probability within the context of rolling a die.. . .
# 272 :: 7/10/08	What is z-score? what information is provided by a z-score?. . .
# 271 :: 7/9/08	Which type of data set can the mean not be calculated?. . . skew, mean, Geometric Mean, Median
# 269 :: 7/9/08	A classical experiment in extrasensory perception (ESP) consists of asking a subject to tell, without looking, the suit of each card in a deck of Zene. . . Z-Score, Binomial Probability, Normal Approximation, binomial, BINOMDIST
# 268 :: 7/9/08	How would you demonstrate the Central Limit Theorem to classmates. . .
# 267 :: 7/8/08	how can i compute for the standard scores when i don't know what the SD is?. . .
# 266 :: 7/8/08	what is the difference between percentage and percentile?specially in cat like exams.. . . Percentile
# 265 :: 7/6/08	An auditor reviewed 25 oral surgery insurance claims from a particular surgical office, determining that the mean out-of-pocket patient billing above . . . 1-sample t-test
# 263 :: 7/6/08	Determine the critical value Za/2 that corresponds to 94% level of confidence Compute the 90% confidence interval about m if the sample size, n, is. . . Critical Value, Confidence Intervals, Margin of Error
# 262 :: 7/3/08	with a mean of 150 and a standard deviation of 15 what is the probability of a student having a weight of less than 178 lbs.. . . Z-Score
# 261 :: 7/1/08	If your hypothesis is not correct, can the data collected still be used within a subsequent analysis.. . . Hypothesis Test, p-value
# 260 :: 7/1/08	Suppose that the scores of architects on a particular creativity test are normally distributed. What percentage of architects have Z scores (a) above . . . Z-Score
# 259 :: 7/1/08	What is the formula used to get percentile from z-score? I have z-scores but am using excel and want to be able to type in a formula to figure percen. . . NORMSDIST
# 257 :: 6/30/08	A company is filling bags of rock salt to a level of 50 pounds. It believes that all bags are filled correctly, but would like to use a hypothesis tes. . . Null Hypothesis , Alternative Hypothesis
# 256 :: 6/30/08	19. A doctor reports that he/she has been experiencing a 15% rate of no-shows on appointments. Among 150 appointments, find the probability that ther. . .
# 254 :: 6/28/08	Body Temparatures. Human body Temp have a mean of 98.20F and standard deviation of 0.62F. Convert the given temparatures to z scores. A. 97.5F B. 9. . .
# 253 :: 6/26/08	What are the 2 advantages of using Z power? If the z score is less than 0, what can be said of the corresponding raw score? If the z score is great. . . Z-Score
# 252 :: 6/26/08	Examine the data below showing the weights (in pounds) of randomly selected checked bags for an airline's flights on the same day. (a) At α = .05. . .
# 251 :: 6/25/08	How can I calculate the z-score for 2 test data that come from 2 tester, eg: 378 and 362?. . .
# 250 :: 6/24/08	1)For n = 49, find the 90% confidence interval for x bar = 85 and ó = 2. Do not round! 2)A purchasing agent for a national chain of seafood restaur. . .
# 249 :: 6/24/08	A nationally standardized test is scaled so that the normally distributed scores have a mean of 80 and a standard deviation of 10 in the population. I. . . Z-Score
# 248 :: 6/24/08	the class ends the year with a mean of 68 and a stadard deviation of 9, the prof decides to bell curve the marks so that the top 10% gets an A (80%). . . .
# 247 :: 6/24/08	Jeff: Can you possibly share the actual formula you are using in this application to produce the Adjusted Wald calculations? Thanks. . . Adjusted Wald, Z-Score, Confidence Intervals
# 245 :: 6/22/08	Use the traditional method to test the given hypothesis. Assume that the samples are independent and that they have been randomly selected A resea. . .
# 244 :: 6/22/08	Mean output of solar cells of three types are measured six times under random light intensity over a period of 5 minutes, yielding the results shown. . . .
# 243 :: 6/22/08	Examine the data below showing the weights (in pounds) of randomly selected checked bags for an airline's flights on the same day. (a) At α = .05. . .
# 242 :: 6/19/08	When would you use regression correlation at your place of employment, in your education, or in politics. . .
# 241 :: 6/19/08	a university's administrator proposes to do an analysis of the proportion of graduates who have not fuond employment in their major field one year aft. . .
# 240 :: 6/17/08	Estimate probability P(6) for a binomial experiment within = 18, p = 0.30 by using the normal distribution. . .
# 239 :: 6/16/08	I have a data set where n=20. My problem is to find the score at exactly the 75th percentile assuming normality. I know the formula for z-score, the. . . Z-Score
# 238 :: 6/15/08	A random sample of rivets from 2 suppliers were compared to see what the mean diameter was from each and a test to determine whether the population me. . .
# 237 :: 6/14/08	A sample of 100 one-dollar bills from the Subway cash register revealed that 16 had something written on them besides the normal printing (e.g., “Bob . . .
# 234 :: 6/13/08	The third quartile of the age at marriage for females in US last year was 29.5 years. What percentage of women who married in the US last year were ol. . . Quartile
# 233 :: 6/13/08	Between what two values of Z will 88% of the middle data values fall between?. . . Z-Score
# 232 :: 6/12/08	If a distribution of test scores is normal with a mean of 78 and a standard deviation of 11, what percent of the area lies below 60. . . Z-Score
# 231 :: 6/12/08	A person gets 14/20 on a test in which each question has 5 answer choices. What is his 95% CI for his score?. . .
# 230 :: 6/11/08	a score that is 8 points above the mean corresponds to a z-score=0.05 What is the population standard deviation?. . . Standard Deviation, Z-Score
# 229 :: 6/11/08	Hi, what is the formula for converting z-scores to percentiles? I want to build a tool in Excel so i can get percentiles from test scores on normally . . . NORMSDIST
# 227 :: 6/10/08	how actually p value represents a distribution pattern whether it is normal or not? u explain the anderson-darling test regarding the normal graph. . .
# 225 :: 6/9/08	How do we calculate the upper and lower limits of one sided and two sided 95% confidence level of difference in proportion when comparing two groups i. . .
# 224 :: 6/8/08	I have some datas of arsenic concentration blockwise. can it be possible to compare the datas graphically, for blockwise distribution of the arsenic. . . Interaction Plot
# 222 :: 6/7/08	Fitness club surveys randomly selected members and found that the average weight of those questioned is 157 lb. Is this a parameter or a statistic?. . . Parameter, statistic
# 219 :: 6/6/08	A z score of 1.04 shows a percentage value of?. . . Z-Score
# 218 :: 6/5/08	what are the key terms in a verbal hypothesis that signify whether you are conducting a one-tailed or two-test? Give an example and explain your answe. . . Hypothesis Test, One-Tailed Area
# 217 :: 6/5/08	Volunteers at a teenage distress center have been assigned based on their skills and expertise. It's assumed that 40% are drug related, 25% sex relate. . .
# 215 :: 6/3/08	Annual starting salaries for college graduates with degrees in business administration are generally expected to be between $30,000 and $45,000. Assum. . . Standard Normal Curve, Confidence Intervals, Standard Deviation, Normally Distributed
# 214 :: 6/2/08	I am charged with sampling expense report submissions for accuracy. We get 8000 T&E claims, and want to sample a subset making inferences about the p. . . 1-sample t-test, Confidence Intervals, Sample Size
# 213 :: 6/1/08	Let X be a random variable with the following probability distribution. Find the expectation and variance E(X) Var (X)of X. Value x of X P(X=x). . .
# 212 :: 6/1/08	How would I figure out a 90% and 95% confidence interval for the below informaion? What would be the formula? Can I figure this out in Excel or Mega. . . t-distribution, Confidence Intervals, TINV, Margin of Error
# 211 :: 5/29/08	State the main points of the Central Limit Theorem for a mean. B. Why is population shape of concern when estimating a mean? What does sample size hav. . . Central Limit Theorem, Sample Size
# 210 :: 5/29/08	My local coffee house sells Colombian coffee beans to supermarkets in bags labelled 100g each. The tolerance of the automatic filling machine, lead. . . Z-Score
# 209 :: 5/29/08	In 1992, the FAA conducted 86,991 pre-employment drug tests on job applicants who were to be engaged in safety and security relatd jobs and found that. . . Central Limit Theorem, binomial, Normal Approximation, Confidence Intervals
# 208 :: 5/27/08	I am comparing 2 proportions of patients (before and after the introduction of a new quality-of-care project). The project is expected to reduce the p. . . 1-Sided Test, Hypothesis Test
# 207 :: 5/24/08	Suppose that the scores of architects on a particular creativity test are normally distributed.What percentage of architects have Z scores. (a) abov. . . Z-Score
# 206 :: 5/24/08	The variable Z has a standard Normal distribution. a) Find the number z that has cumulative proportion 0.85. b) Find the number z such that the eve. . . Z-Score
# 205 :: 5/22/08	Find the number z that has cumulative proportion 0.8. . . Z-Score
# 204 :: 5/22/08	What does a z value mean?. . . Z-Score, Z-value, Standard Score
# 203 :: 5/22/08	How to determine the sample size for comparing mulltiple parameters like Height , weight, Blood pressure , Blood parameters like blood glucose, total. . . Sample Size, Power, ANOVA, t-test
# 202 :: 5/21/08	Site preparation for new housing developments for tracts of 40 houses is normally distributed with a mean of 250 workdays and a standard deviation of . . . Z-Score
# 201 :: 5/20/08	Hi I am running a study comparing 3 different products on five different experimental visits. The same subjects are used for each visit and the same. . . Counterbalance
# 200 :: 5/19/08	I've calculated the confidence intervals about a regression line. My data is log transformed and has high R-square value for what is called "power" e. . .
# 199 :: 5/19/08	A local bakery determines that the probability of a customer ordering a blueberry muffin is 50%. 5 customers come into the bakery. A. What is the pr. . . Binomial Probability, binomial
# 198 :: 5/17/08	Find the value of Z a/2 that corresponds to a level of confidence of 98.22 percent.. . .
# 197 :: 5/15/08	Annual starting salaries for college graduates with degrees in business administration are generally expected to be between $30,000 and $45,000. Assum. . . Normally Distributed, Standard Deviation, Margin of Error, Sample Size
# 195 :: 5/14/08	Time/CNN voter polls monitored public opinion for the presidential candidates during the 2000 presidential election campaign. One Time/CNN poll conduc. . .
# 194 :: 5/14/08	Why should you use ANOVA instead of several t tests to evaluate mean differences when an experiment consists of three or more treatment conditions?. . . Bonferroni correction, ANOVA, Type I Error
# 193 :: 5/14/08	How can I determine the sample size for data that is discrete but not binary?. . .
# 191 :: 5/12/08	When would you use regression correlation at your place of employment, in your education, or in politics?. . .
# 190 :: 5/12/08	200 people were sampled and the following table shows the number of people with a certain average electric energy usage based upon the type of home an. . . Addition Rule, Mutual Exclusive
# 189 :: 5/12/08	A sample of PVC pipes coming off a production line were tested for pipe diameter size. The statistical results (in millimeters) were: Mean 300 . . . Normal Rule, Normal Curve, Bell Curve, Normal Distribution
# 188 :: 5/12/08	How do I do a Chi-Square test on unequal sample sizes?. . . Chi-Square, Unequal Sample Size
# 186 :: 5/9/08	how does altman build z-score? please send to my email the process of building this score!. . . Altman Z-Score, Z-Score
# 185 :: 5/7/08	Hi I am performing a regression analysis with 3 x variables. My question is, if I have high p values (i.e. above 0.05) for each of the x coefficie. . . Regression Analysis, collinearity, Correlation
# 183 :: 5/7/08	I am trying to apply the problem discovery sample size formula to several finite populations. How should I integrate the finite population correction. . . Problem Discovery, Finite Population
# 182 :: 5/5/08	When would you use a hypothesis test for the difference in two population proportions at your place of employment, in your education, or in politics?. . . Hypothesis Test, Two-Proportion Test
# 181 :: 5/5/08	What is the difference between a population standard deviation and a sample standard deviation?. . . Standard Deviation, Degrees of Freedom
# 180 :: 5/5/08	How to convert a exam score (standard score) back to Percent score? e.g. Total of students 16, 71 76 56 79 74 72 68 75 77 61 81 75 7. . . Standard Score, Percentile, Percent Score
# 177 :: 5/2/08	Find the probability that a randomly selected adult has an IQ that is less than 130. . . IQ Score, Z-Score
# 176 :: 4/30/08	In a 0ne-tail test (l side) with z score of 1.645, what are the percentages for critical value and non-critical value?. . . One-Tailed Area, Z-Score, Critical Value
# 175 :: 4/28/08	Suppose that in NY State, 35% of voters are Democrats, 30% are Republicans, and 11% are independent. You are conducting a poll by randomly calling reg. . . Probability, Multiplication Rule, Binomial Probability, Choose, binomial, Binomial pmf, Binomial cdf
# 173 :: 4/27/08	why can you not have a z- score equaling 0/0 ? what is problematic with calcutlating a z-score for a data set of repeated entries?. . . Z-Score
# 172 :: 4/27/08	The library is to be given 3 books as a gift. The books will be selected from a list of 18 titles. If each book selected must have a different title, . . . Choose, Combination
# 170 :: 4/25/08	If last six month average defect rate is 5% then what will be the process Zst score? . . . 1.5 Sigma Shift, Z-Score, Z Short Term
# 169 :: 4/25/08	Various temperature measurements are recorded at different times for a particular city. The mean of 25C is obtained for 60 temperatures on 60 differen. . . Null Hypothesis , Alternative Hypothesis , t-statistic, Z-Statistic, 1-sample t-test
# 167 :: 4/24/08	I know that 33 is the raw score of the 85th percentile. How do I determine the mean?. . . Percentile, Standard Deviation
# 166 :: 4/23/08	What is the equation to go from a Z-score to a percent? I know how to use the table but i want to know the actual formula/equation.. . . Newton-Raphson
# 164 :: 4/23/08	how to calculate one sided 95% confidence limits for a proportion.could you provide a formula . . . Adjusted Wald, Confidence Intervals, One-Tailed Area
# 163 :: 4/22/08	When calculating confidence interval estimates...how is the x and standard deviation calculated?. . . Standard Deviation, Confidence Intervals
# 162 :: 4/22/08	I am trying to do A/B testing onweb page displays. One is the test the other is the control. Could you help me determine the formula for sample size . . . Confidence Intervals, Control Chart, A/B Testing, p-chart
# 161 :: 4/21/08	z Scores lenths are measured in centameters, does it have to be converted to a different unit of measurment? . . . Z-Score
# 160 :: 4/21/08	in a sample of 1000 tv vieweres 330 watched a particlar programme. find 99 pecent confidence limits for tv viewers who watched this programme. . . Confidence Intervals, Adjusted Wald
# 159 :: 4/18/08	A parameter is a population characteristic. The numerical value of a parameter usually cannot be determined because we cannot measure all units in th. . .
# 158 :: 4/18/08	If I have a set of values(direct measurements of dynamic deformations of a road at 100m) between 3 and~1000, how can I calculate the 2 characteristica. . . Monte-Carlo, Student-t, t-distribution
# 157 :: 4/17/08	With a z score of 1.5, what percentage often scores are above 52 and what percentage of the scores are above 60?. . . Z-Score
# 156 :: 4/16/08	Could you please tell me in what situation the maentl hanszel test is more appropriate than using chi square. I believe maentl hanszel is used when a . . .
# 155 :: 4/16/08	difference between a sample parameter ( X-bar and s ) and a proportion parameter ( p )? . . . x-bar, Standard Deviation
# 154 :: 4/15/08	I can do the math in all of my Probability & Stats 101 questions, but I can't tell which formula to use for what question. How can I interpret the wor. . .
# 153 :: 4/14/08	You survey a sample of 10 college students to measure their racial prejudice using a scale of 0 (no prejudice) to 100 (extreme prejudice). Here are t. . . skew, Median
# 152 :: 4/14/08	If 350 respondents out of a random sample of 1,000 Americans reported that they did not trust their government, what is your estimation at a 99% confi. . . Adjusted Wald, Confidence Intervals
# 151 :: 4/14/08	A random sample of 25 households finds that an average of 2.3 people reside in each house (the standard deviation is 0.35). With a 95% confidence lev. . . TINV, t-statistic, t-distribution, Confidence Intervals, Standard Error of the Mean, Margin of Error
# 150 :: 4/14/08	Exploitron, Inc. conducts a random survey of 700 of their workers and finds that the average employee earns $31,782 per year, with a standard deviatio. . .
# 149 :: 4/14/08	You are interested in whether men participate more than women in political activities, so you survey 632 men and 675 women and ask them how many polit. . . 2-sample t-test, t-statistic, t-test
# 147 :: 4/12/08	find the midrange for the given sample data. 1.5 2.5 3.0 1.2 1.3 3.8 1.8 3.3 2.3 2.9 1.8. . . Mid-range
# 146 :: 4/9/08	what is the z-score that corresponds to the 20th percentile of the normal distribution. . . Z-Score, Percentile
# 145 :: 4/8/08	Will the t statistics calculated from 4 observations valid?. . . t-statistic, t-distribution, Small Sample
# 144 :: 4/8/08	In a council election, 5 people are running, 3 seats available, and you want two for sure to win,but no caring who the third is. Should you only vote. . .
# 143 :: 4/7/08	how to interpret the z- score. . .
# 142 :: 4/7/08	Opposed to death penalty. Year 2000- 801 opposed out of 2565. Year 1993 337 opposed out of 1488. I have two samples, one is 31.2% and one is 22. . .
# 141 :: 4/7/08	whwn we say six sigma, does it mean six sigma on either side of the axis or is 3 sigma on either side. . . Six Sigma
# 140 :: 4/7/08	Prediction of business failure using statistical methods. . .
# 139 :: 4/6/08	how do you calculate the appropriate analysis. . .
# 138 :: 4/4/08	You can win $100 if you succeed in any one of the following: 1) draw a spade from a fresh deck of cards; 2) draw a heart from a fresh deck of cards; . . .
# 137 :: 4/4/08	What score would Sandra need to beat 91 percent of her mathematics class? The mean score was 73, and the standard deviation was 12.. . . Z-Score
# 136 :: 4/4/08	Ran parts and found 1% defective(1 out of 100). Made a change to the process and want to rerun parts. How many parts do we need to check (and find 0% . . . Process Sigma, DPMO
# 135 :: 3/31/08	I am conducting a ring test where 6 laboratories were asked to measure protein levels in the same flour sample. I then calculated the z score for each. . . Z-Score
# 133 :: 3/31/08	When number of Passed is half of total Tested, why all points estimates are 0.50. Tk. . . Standard Score
# 132 :: 3/30/08	why use 6sigma instead of 5 or 4sigma in calculating process capability. . . Six Sigma, DPMO, Process Sigma, Sigma Level
# 131 :: 3/29/08	which statistic technique can i use.. when i apply three treatment(treatment 1, treatment2, treatment3)on 2 dependent variable?(i applied 3 treatments. . .
# 130 :: 3/28/08	what is the value of 1sigma 2sigma 3sigma 4sigma 5sigma 6sigma. . . Six Sigma
# 129 :: 3/27/08	Hi when we have several criteria with different scale, for ranking can we add values after standardization? for exaample for ranking websites we have. . .
# 128 :: 3/25/08	What is the value of z score required for a 70% confidence interval?. . . Z-Score, , Confidence Intervals
# 127 :: 3/25/08	can anyone explain? Age so individuals in a certain population are normally distributed with a mean of 55 and standard deviation of 10 years. What age. . .
# 126 :: 3/22/08	what is the distinction between a qualitative and a qualitative measure?. . .
# 125 :: 3/20/08	When testing two populations with small sample sizes, do both sample sizes have to be identical? Why or why not?. . . Unequal Sample Size
# 124 :: 3/20/08	What constitutes a small sample size in a test of two populations? . . . t-distribution, Z-Statistic, Small Sample
# 123 :: 3/20/08	How does a non-parametric business scenario differ from a parametric business scenario?. . .
# 122 :: 3/20/08	When would you use a hypothesis test for the difference in two population proportions at your place of employment?. . .
# 121 :: 3/20/08	What is the differences among a proportion, a percentage, and a ratio?. . .
# 120 :: 3/20/08	What statistics test should I be using when I am assessing whether subjects were able to complete a task (i.e. Yes/No nominal data) before instruction. . .
# 119 :: 3/20/08	Is is possible to modify a semantic differential scale into a 10-point scale? If so, should the data be treated as ordinal or interval? . . . Bell Curve, ANOVA, Ordinal, Interval
# 117 :: 3/19/08	What is the significance of the picture at the top of the t-table? What is the difference between a sample parameter (X-bar and s) and a proportion pa. . .
# 116 :: 3/18/08	Hi. I'm going to run a nested model in logistic regression. I have a dependent variable (nest) and I have two sexes (male/female). I can not run this. . .
# 114 :: 3/16/08	The mean on this test is 3.5 with a standard deviation of .5. Billy scores 5. What is the standard score?. . . Standard Score, Z-Score
# 113 :: 3/16/08	How do you find the value of r?. . .
# 112 :: 3/13/08	getting the formular for confindence interval. . .
# 111 :: 3/12/08	Expected Project duration:25 days Probability for 27 days Standard deviation :5.656. . .
# 110 :: 3/12/08	If I have unnormal data with n=15, and there are 2 samples. What test do I use? How do I make the data normal if the samples contain zero, b/c it's . . .
# 109 :: 3/10/08	A director of a social agency is planning to hire temporaty staff to assist with intake. In making plans, the director needs to know whether there is. . .
# 108 :: 3/10/08	Compute a chi-square test for goodness of fit for each of the following, using the .05 level for each. In each problem, the expected distribution is . . .
# 107 :: 3/10/08	Suppose a candidate running for sheriff claims that she will reduce the average of emergency response to less than 30 minutes. (30 minutes is thought. . .
# 106 :: 3/10/08	suppose that the scores of architects on a particular creativity test are normally distributed. What percentage of architects have Z scores?. . .
# 105 :: 3/10/08	For large correlations, the SAS program simply states that p < .0001. But to conduct a meta-analysis I need to know the exact p values for large corr. . .
# 104 :: 3/9/08	Trimmed mean, 80% trimmed mean = ? was a question on a homework assignment. When I read my notes the teacher had written 10 values, then eliminat. . .
# 103 :: 3/9/08	What is the Standard Deviation of a z-score?. . .
# 102 :: 3/3/08	How can a t test be employed in hypothesis testing by the use of directional vs. nondirectional hypotheses?. . .
# 101 :: 3/3/08	When is using the t statistic a more appropriate alternative to using a z-score? . . .
# 100 :: 3/3/08	i am trying to figure out the best means to calculate the reliabilty of our work load index ie a measure of work load per empolyee per hour - is there. . .
# 99 :: 3/2/08	what is the mean of the z score. . .
# 98 :: 3/1/08	Given the linear correlation coefficient r and the sample size n, determine the critical values of r and use your finding to state whether or not the . . .
# 97 :: 3/1/08	A medical school claims that more than 28% of its students plan to go into general practice. It is found that among a random sample of 130 of the scho. . . Normal Approximation to Binomial , BINOMDIST, Continuity Correction, 1-Sample Proportion Test, 1-Proportion Test
# 96 :: 3/1/08	The mean is ì = 60.0 and the standard deviation is ó = 4.0. Find the probability that X is less than 53.0.. . . Z-Score
# 94 :: 2/29/08	In one town, 36% of all voters are Democrats. If two voters are randomly selected for a survey, find the probability that they are both Democrats.. . .
# 93 :: 2/29/08	I have two contingency tables. One has a chi-square value of 14.40 and the other is 27.86. Both have 6 degrees of freedom. Based on an alpha of .01. . .
# 92 :: 2/28/08	Which has the tighter spec limits, 3 sigma or 6 sigma?. . .
# 91 :: 2/24/08	IQ tests generally have scores in which the mean is 100, and the standard deviation is 16. If your IQ score was 134, what percentage of the population. . . Normal Curve
# 90 :: 2/23/08	The cholesterol levels of a population have a normal distribution with a mean of 160 and a standard deviation of 30 how you I find the percentage of t. . .
# 89 :: 2/22/08	Where is using the t statistic an appropriate alternative to using a z-score?. . .
# 88 :: 2/20/08	How do you calculate the standard deviation from the confidence interval?. . .
# 86 :: 2/19/08	For a standard normal curve, whats the z-score that corresponds to the third quartile . . .
# 84 :: 2/19/08	If you record data for a year, and find that the mean number of women in shelters is 250, with a standard deviation of 75, and the distribution is nor. . .
# 83 :: 2/18/08	Dear Jeff Sauro, We found your website very interesting, and were hoping that you could provide some insight into a question we have concerning a pot. . .
# 82 :: 2/14/08	In a previous study, drug X had a side effect that is seen 50% in women and %80 in men. Howmany patients must be included in a new study (0.80 (beta) . . .
# 81 :: 2/10/08	calculate the z score of 9o th percentile?. . .
# 80 :: 2/4/08	How do you determine percentage of brackets (that hold struts) created with misaligned holes? What is a calculation in determining a percentage of bra. . .
# 79 :: 2/4/08	How do you figure the individual X value of interest. . .
# 78 :: 1/23/08	What does measuring the standard deviation of a set of data tell you about the data. . .
# 77 :: 1/22/08	How should I compute probability in spss for variable "seizure duration" with unnormal distribution which constitutes numerical data of duration in se. . .
# 76 :: 1/20/08	How do you use the spss table?. . .
# 75 :: 1/20/08	Students given exam with 300 multiple questions, distribution was normal and mean 195 with a standard deviation of 30. What were the scores of the st. . .
# 70 :: 12/10/07	The grades on the midterm given in a large managerial stats class are normally distibuted with mean 75 and standard deviation 9. Instructors of this c. . . Z-Score, Percentile
# 67 :: 11/6/07	Among the contestants in a competition are 35 women and 20 men. If 5 winners are randomly selected, what is the probability that they are all men?. . .
# 66 :: 11/6/07	The probability that Luis will pass his statistics test is 0.44. What is the probability that he will fail his statistics test?. . .
# 65 :: 10/31/07	If a standard deviation of a set of data is zero, what can you conclude about the set of values?. . .
# 64 :: 10/29/07	On what method is the Excel based calculator that you have provided based on (Exact, Score, Wald, Adjusted Wald). Also, what method is the calculation. . .
# 63 :: 10/29/07	How do you compare confidence levels?. . .
# 62 :: 10/29/07	If I had 6600 wigets, how many do I have to test with 0 failures to show 95% of them are acceptable with a 95% confidence?. . .
# 61 :: 10/29/07	What is the connection between the confidence level and the confidence interval?. . .
# 60 :: 10/29/07	How do you calculate asymmetric confidence intervals?. . .
# 59 :: 10/29/07	How could we rescreen for defective units from a population of 900 units and establish a 95% confidence that the whole 900 units are acceptable.? How . . .
# 58 :: 10/29/07	Why don't statisticians calculate 100% confidence intervals?. . . Confidence Intervals, Confidence Level
# 57 :: 10/29/07	In order to calculate dpmo, why do you need multiply 1 million?. . . DPMO
# 56 :: 10/29/07	It seems the normal distribution function in excel requires more arguments than specified in this article.. . .
# 55 :: 10/29/07	How do you interpret a z-score?. . .
# 54 :: 10/29/07	What is the actual formula for finding the exact probability from the z-score without having to use the table?. . .
# 53 :: 10/29/07	Can you have a negative z-score?. . .
# 52 :: 10/29/07	What is the z score for 10?. . .
# 51 :: 10/29/07	How do you get x bar?. . .
# 50 :: 10/29/07	What is the DPMO calculation for a discrete task?. . .
# 49 :: 10/29/07	How do you calculate T scores?. . .
# 48 :: 10/29/07	Suppose that the scores of architects on a particular creativity test are normally distributed. What percentage of architects have Z scores? a. above . . . Z-Score
# 47 :: 10/29/07	Calculate the z score for a raw score of 10 from the folowing scores:10,20,25,5,30. Based on your anser ,approximately what percentile does the raw sc. . .
# 46 :: 10/29/07	How to calculate a Z-value for Altman's Bankruptcy Formula?. . . Altman Z-Score
# 45 :: 10/29/07	How do you standardize data?. . . Standardize
# 44 :: 10/29/07	Can you get a z score for both a sample and a population?. . .
# 43 :: 10/29/07	What is the Z-score formula for EXCEL?. . . Excel
# 42 :: 10/29/07	What are the units of z-score?. . . Z-Score, Units of Measure
# 41 :: 10/29/07	On a scale from 0 to 100, the mean level of economic development among the countries in the world is 65 and the standard deviation is 10. What proport. . . Z-Score, Standard Normal Curve
# 40 :: 10/29/07	What are the properties of the z-score in data analysis?. . .
# 39 :: 10/29/07	What is the basic formula for the z-score other than table of areas?. . . Newton-Raphson, Z-Score
# 38 :: 10/29/07	Alexa got 144 on her test which has a mean of 128 and a standard deviation of 34. What is her z-score?. . . Z-Score, example
# 37 :: 10/29/07	How do you calculate the z score for the raw score of 10 based on the following distribution: 8, 9, 15, 30, 7, 8 ?. . . Z-Score, Standard Deviation
# 36 :: 10/29/07	What is the formula for finding the z score for a population ?. . .
# 35 :: 10/29/07	Can you please explain the 1.5 sigma shift they use in determining process sigma?. . . 1.5 Sigma Shift
# 34 :: 10/29/07	How do you get a Z score from a standard deviation?. . .
# 33 :: 10/29/07	How do you find a z score such that 8% of the area under the curve is to the right of Z?. . . Z-Score, One-Sided Area
# 32 :: 10/29/07	What proportion is Less than 52. With mean of 67.56 and standard deviation of 25.7. . .
# 31 :: 10/29/07	What is the Z score of a 98% confidence interval?. . . Confidence Intervals, Confidence Level
# 30 :: 10/29/07	How is a z score measured?. . .
# 29 :: 10/29/07	How do you calculate a z-score on discrete data?. . . Z-Score, Discrete Data
# 28 :: 10/29/07	What is one of the two differences between the way ZST or ZLT are calculated?. . . Z Short Term, Z Long Term
# 27 :: 10/29/07	What does percentile rank mean?. . . Percentile, Percentile Rank
# 26 :: 10/29/07	How do you calculate z-scores from batting averages?. . . Z-Score
# 25 :: 10/29/07	What does a Z-score look like on a graph?. . . Z-Score
# 24 :: 10/29/07	Using the standard normal table, the total probability to the right of z=2.18 and to the left of z=1.75 is?. . . Normal Table, One-Tailed Area, One-Sided Area
# 23 :: 10/29/07	How do you calculate z-score for x-bar 2.7,u=3,s=1 and n=100 ?. . .
# 22 :: 10/29/07	How do you standardize the height of a 10-yr old boy of 134.2cm ?. . . Standardize
# 21 :: 10/29/07	How do you calculate standard deviation?. . . Standard Deviation
# 20 :: 10/29/07	I want to know why we call six sigma statistically , i mean how six sigma is 50% of tolerance. . .
# 19 :: 10/29/07	Does a sigma value relate the voice of the process to the voice of the customer?. . . QFD
# 18 :: 10/29/07	What is sample variance?. . .
# 17 :: 10/29/07	Having obtained the z score and then derived the percentage... what does the percentage tell you?. . . Unusual Event, Z-Score
# 16 :: 10/23/07	What is the Trimmed Mean For?. . . Trimmed Mean, Task Time
# 15 :: 10/23/07	How do you calculate a Z-score with a two-sided specification limit? What is the DPMO? I have a lower spec limit of -0.008 and an uppers spec lim. . . DPMO, Z-Score, Process Sigma, Z-upper
# 14 :: 10/23/07	What percent of the time should this occur? (Z-Score) ?. . . Z-Score, Normally Distributed, Standard Deviation, Normal Curve
# 13 :: 10/23/07	How unusual is this event (Z-Score)? A department store, on average, has daily sales of $28,707.47. The standard deviation of sales is $1000. . . . Z-Score, Unusual Event
# 12 :: 10/23/07	Can a z score be calculated by input of a proportion only?. . . Proportion, Z-Score
# 11 :: 10/23/07	What is the z value for 1.648?. . . Z-Score
# 10 :: 10/23/07	What is the difference between a Z-Scores and Process Sigma?. . . Process Sigma, Z-Score, 1.5 Sigma Shift
# 9 :: 10/23/07	How do you make data normally distributed?. . . Transformation, Log Transformation, Monte-Carlo, Bootstrap, Non-Normal Data, Normal Distribution, Non-Parametric
# 6 :: 10/23/07	How do you determine the sample size for data for which the mean and standard deviation are not known?. . . Standard Deviation, Sample Size, Margin of Error
# 5 :: 10/23/07	If you have a normal distribution of a random variable x, with a mean of 56 and standard deviation of 8: What is the probability that the random varia. . . Nomal Distribution, Normal Curve
# 4 :: 10/23/07	Where can I find a Z score chart ?. . . Z-Score
# 3 :: 10/23/07	What is the critical z score for a one tailed test with alpha = .01.. . . Alpha, Z-Score
# 2 :: 10/23/07	Joe received a z score of -1.50 on a classroom test. This means that, compared to his classmates, Joe's score was...?. . . Z-Score, 1.5, lambda

Copyright © 2004-2019 Measuring Usability LLC